Production of insecticidally active vinyl-cyclopropane carboxylic acid esters

ABSTRACT

Insecticidally active vinyl-cyclopropane carboxylic acid esters of the formula ##STR1## are prepared by reacting ##STR2## in which R 12  is a radical selected from the group consisting of ##STR3##  with an alcoholate of the formula 
     
         M--O--R.sup.8. 
    
     Various processes for making the intermediates are also described. Many of the intermediates and end products are new.

This is a division of application Ser. No. 827,514, filed Aug. 24, 1977,now abandoned.

The present invention relates to an unobvious process for thepreparation of certain vinyl-substituted cyclopropanecarboxylic acidesters, some of which are known, which can be used as intermediates forthe preparation of insecticidally active compounds or which can be usedthemselves as insecticides.

The present invention also relates to certain new vinyl-substitutedcyclopropanecarboxylic acid esters as well as to intermediates for theirpreparation.

Various chrysanthemumic acid esters, for example the pyrethrins,jasmolins or cinerins, are naturally occurring cyclopropanecarboxylicacid esters having an insecticidal action. They possess valuableproperties which, however, are impaired by, for example, easy oxidativedegradation. Synthetic products have also been found, for examplem-phenoxybenzyl or 5-benzyl-3-furylmethyl esters of2,2-dimethyl-3-(β,β-dihalogenovinyl)-cyclopropanecarboxylic acids, theinsecticidal activity of which is said to be higher than that of thecorresponding chrysanthemumic acid esters. In addition, the syntheticproducts are said to have a higher stability towards oxidativedegradation (Nature 244, 456 (1973); J. Agr. Food. Chem. 21, 767(1973)).

Various processes for the synthesis of these synthetic products areknown.

The reaction of diazoacetic acid esters with1,1-dichloro-4-methyl-1,3-pentadiene leads, after hydrolysis, to2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid which issuitable for use as an intermediate for the synthesis of pyrethroids(Coll. Czech. Chem. Commun. 24, 2230 (1959)).

The ozonization of naturally occurring chrysanthemumic acid esters gives2,2-dimethyl-3-formyl-cyclopropanecarboxylic acid esters asintermediates for the Wittig reaction withtriphenyldichloromethylenephosphorane (South African PatentSpecification No. 733,528).

However, these processes can be carried out on a relatively large scaleonly with difficulty.

Further processes which lead to2,2-dimethyl-3-(β,β-dihalogenovinyl)-cyclopropanecarboxylic acids andesters have been disclosed. Thus, certain allyl alcohols are reactedwith ortho-esters and subjected to a rearrangement reaction at 160° C.An addition reaction with CCl₄, which may take place by a free radicalmechanism, and subsequent cyclization give the carboxylic acidderivatives, from which the acids mentioned above can be obtained. Inthis process, various by-products are formed in the individual reactionstages and some of these products can make it difficult to isolateintermediate stages and their presence is evidenced by reduced yield(German Offenlegungsschriften (German Published Specifications) Nos.2,539,895 and 2,544,150).

The known processes for introducing, in particular, a halogenovinylgroup in the 3-position of the cyclopropanecarboxylic acid have,according to circumstances, various disadvantages, of which thefollowing can be particularly serious:

(1) formation of undesired by-products,

(2) relatively high reaction temperatures in some cases,

(3) several reaction stages and

(4) relatively low total yields over all reaction steps.

The processes mentioned above are thus ill-suited to the industrialpreparation of many cyclopropane-carboxylic acid esters containingdifferent substituents.

Furthermore, it has been found that vinyl-substitutedcyclopropanecarboxylic acids can be obtained by allowingmonochloroketene, produced in situ, to act on ethylenically unsaturatedcompounds (German Offenlegungsschrift (German Published Specification)No. 2,539,048).

However, this process is not universally applicable and can be carriedout only with ethylenically unsaturated compounds wherein the doublebond is activated by suitable substituents.

(1) The present invention provides a process for the preparation of avinyl-substituted cyclopropanecarboxylic acid ester of the generalformula ##STR4## in which

R¹, R² and R³, which need not be identical, each represent hydrogen,halogen, CN, optionally substituted alkyl or alkenyl, aralkyl, aryl,alkoxycarbonyl, dialkylaminocarbonyl, acyloxy, alkylsulphonyl orarylsulphonyl,

R⁴, R⁵, R⁶ and R⁷, which need not be identical, each represent hydrogen,optionally substituted alkyl or alkenyl, halogen, CN, aralkyl or aryl,it being possible for any of the pairs R¹ and R², R² and R³, R¹ andR⁴,R⁴ and R⁵,R⁴ and R⁷ and R⁵ and R⁶, conjointly with the adjacentcarbon atom(s), to form a multimembered carbocyclic ring with up to 8ring carbon atoms, and

R⁸ represents an alcoholic radical,

in which process (1.1) an α-halogenocyclobutanone, of the generalformula ##STR5## in which

R¹ to R⁷ have the meanings stated above and

Hal represents halogen,

is reacted with an alcoholate of the general formula

    M--O--R.sup.8                                              (III),

in which

R⁸ has the meaning stated above and

M represents an equivalent of an alkali metal cation or alkaline earthmetal cation,

if appropriate in the presence of a diluent, or (1.2) a cyclobutanone ofthe general formula ##STR6## in which

R¹ to R⁷ have the meanings stated above,

is halogenated, if appropriate in the presence of a diluent, and thehalogenation product is subsequently reacted with an alcoholate of thegeneral formula (III) above, or (1.3) an α-halogenocyclobutanone of thegeneral formula ##STR7## in which

R¹² represents a group ##STR8##

R¹ to R⁷ have the meanings stated above, and

Hal represents halogen,

is reacted with an alcoholate of the general formula (III) above, ifappropriate in the presence of a diluent, or (1.4) a cyclobutanone ofthe general formula ##STR9## in which

R¹² has the meaning stated above,

R¹ and R⁷ have the meanings stated above, and

Hal represents halogen,

is halogenated, if appropriate in the presence of a diluent, and thehalogenation product is subsequently reacted with an alcoholate of thegeneral formula (III),

or in which (2), provided that a new vinyl-substitutedcyclopropanecarboxylic acid ester of the general formula (I) is to beprepared

in which

R¹ and R², which may be identical or different, each have the meaningstated above,

R³ represents halogen, CN, C₂₋₆ -alkyl or substituted C₁₋₆ -alkyl and

R⁴ to R⁸ have the meanings stated above,

(2.1) a cyclopropanecarboxylic acid of the general formula ##STR10## inwhich

R¹ to R⁷ have the meanings stated under 2,

is reacted with an alcohol of the general formula

    R.sup.8 --OH                                               (VIII),

in which

R⁸ has the meaning stated above,

if appropriate in the presence of a basic or acid catalyst and of adiluent and if necessary at an elevated temperature, or

(2.2) a cyclopropanecarboxylic acid of the formula (VII) is reacted withan inorganic or organic acid halide and the cyclopropanecarboxylic acidhalide formed is subsequently reacted with an alcohol of the formula(VIII), if appropriate in the presence of a base, or

(2.3) the alkali metal, alkaline earth metal or ammonium salt of acyclopropanecarboxylic acid of the formula (VII) is reacted with acompound of the general formula

    R.sup.8 --R.sup.9                                          (IX),

in which

R⁸ has the meaning stated above and

R⁹ represents halogen, methanesulphonoxy, benzenesulphonoxy,p-toluenesulphonoxy or a radical --O--SO₂ --O--R⁸, or

(2.4) a C₁ -C₄ alkyl ester of a cyclopropanecarboxylic acid of theformula (VII) is reacted with an alcohol of the formula (VIII), ifappropriate in a diluent and in the presence of a basic catalyst.

The process variants 1.1 to 1.4 for the preparation of thevinyl-substituted cyclopropanecarboxylic acid esters, some of which areknown, are distinguished, in comparison with known processes for thepreparation of such compounds, by the fact that, by choosing suitablestarting compounds, it has been possible to make these vinyl-substitutedcyclopropanecarboxylic acid esters easily, even on a large scale. Inaddition, the processes according to the invention are widely applicableand not limited to certain small groups of compounds. A furtheradvantage of the process variants 1.1 to 1.4 is that it is possible toobtain the desired cyclopropanecarboxylic acid esters directly, withouthaving to isolate the cyclopropanecarboxylic acids on which they arebased. Process variant 1.2, in which cyclobutanones are used directly asthe starting materials, without it being necessary to isolate theα-halogenocyclobutanones or cyclopropanecarboxylic acids which arepossible as intermediate stages, is particularly advantageous.

(3) α-Halogenocyclobutanones of the formula (II) which can be used inprocess variant 1.1 are known (German Offenlegungsschrift (GermanPublished Specification) No. 2,539,048) and can all be prepared in asimple manner:

(3.1) by halogenating a cyclobutanone of the general formula ##STR11##in which

the radicals R¹ to R⁷ have the meanings stated under 1, if appropriateis the presence of a diluent, or

(3.2) by halogenating a cyclobutanone of the general formula ##STR12##in which

the radicals R¹ and R⁴ to R⁷ have the meanings stated under 1,

if appropriate in the presence of a diluent, or

(3.3) by halogenating a cyclobutanone of the general formula ##STR13##in which

R¹² has the meaning stated under 1.3 and

R¹ and R⁷ have the meanings stated under 1, if appropriate in thepresence of a diluent.

(4) The new α-halogenocyclobutanones, which can be used in processvariant 1.1, of the formula (II)

in which

R¹ and R⁷ have the meanings indicated under 1, provided that at leastone of R¹, R² and R³ has a meaning other than hydrogen, methyl oralkoxycarbonyl,

can be obtained, in addition to the processes indicated under 3.1 to3.3, by reacting

(4.1) a 1,3-diene of the general formula ##STR14## in which

R¹ to R⁴ and R⁷ have the meanings indicated under 2, with chloroketeneof the formula ##STR15## which is optionally produced in situ, ifappropriate in the presence of a diluent.

If a vinyl-substituted α-bromocyclobutanone is reacted with sodiumethylate in process variant 1.1, the course of the reaction can berepresented by the following equation: ##STR16##

The α-halogenocyclobutanone of the formula (II) in which the radicals R¹to R⁷ have the meanings stated under 2, are preferably used in processvariant 1.1.

Furthermore, particularly preferred α-halogenocyclobutanones of theformula (II) for use in process variant 1.1 are those in which

R¹, R² and R³, which need not be identical, each represent hydrogen,halogen (especially fluorine, chlorine or bromine), CN, straight-chain,branched or cyclic C₁₋₆ -alkyl or alkenyl [either of which may beoptionally substituted by halogen (especially fluorine or chlorine),C₁₋₄ -alkoxy, CN or C₁₋₄ -halogenoalkoxy], benzyl, phenylethyl, phenylor naphthyl [any of which may be optionally substituted by halogen(especially chlorine), C₁₋₄ -alkyl, C₁₋₄ -halogenoalkyl, NO₂ or CN],C₁₋₄ -alkoxycarbonyl, dialkylaminocarbonyl with 1-4 carbon atoms peralkyl moiety, C₁₋₄ -alkylsulphonyl (especially methylsulphonyl),phenylsulphonyl [optionally substituted by halogen, C₁₋₄ -alkyl, C₁₋₄-halogenoalkyl, NO₂ or CN] or C₁₋₄ -acyloxy (especially acetoxy ortrifluoroacetoxy), and

R⁴ to R⁷, which need not be identical, each represent hydrogen,straight-chain, branched or cyclic C₁₋₆ -alkyl or alkenyl [either ofwhich may be optionally substituted by halogen, (especially fluorine orchlorine), C₁₋₄ -alkoxy or CN], halogen (especially chlorine orbromine), CN or benzyl, phenylethyl, phenyl or naphthyl [any of whichmay be optionally substituted by halogen (especially chlorine), C₁₋₄-alkyl, C₁₋₄ -halogenoalkyl, NO₂ or CN], it being possible for any ofthe pairs R¹ and R², R² and R³, R¹ and R⁴, R⁴ and R⁵, R⁴ and R⁷ and R⁵and R⁶, together with the adjacent carbon atom(s), to form a 5 to 7membered carbocyclic ring.

Especially preferred α-halogenocyclobutanones of the formula (II) arethose in which R¹, R² and R³, which need not be identical, eachrepresent hydrogen, halogen (especially fluorine, chlorine or bromine),CN, acetoxy, benzenesulphonyl, methoxycarbonyl, phenyl,dimethylaminocarbonyl, chlorovinyl, methyl or ethyl, and

R⁴ to R⁷, which need not be identical, each represent hydrogen, methyl,ethyl, cyclohexyl, chlorine or CN, it being possible for the pair R⁵ andR⁶ or the pair R⁴ and R⁷, together with the adjacent carbon atom(s), toform a 6-membered carbocyclic ring.

Particularly suitable α-halogenocyclobutanones of the formula ((II) are:2,2-dimethyl-3-(α-methyl-β,β-dichlorovinyl)-cyclobutanone,2,2-diethyl-3-(α,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclobutanone,2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chlorovinyl)-cyclobutanone,2,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-difluorovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(β,β-dichlorovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2-ethyl-2,3-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-diethyl-3-(β,β-dibromovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(β,β-dibromovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α-ethyl-β,β-dichlorovinyl)-cyclobutanone,2-ethyl-2,3-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(β-bromo-β-chlorovinyl)-cyclobutanone,2,2-dimethyl-4-ethyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2,4-trimethyl-3-(α,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-4-n-butyl-3-(β,β-dichlorovinyl)-cyclobutanone,2-methyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-di-n-propyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-n-butyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chloro-β-methoxycarbonylvinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dicyanovinyl)-cyclobutanone,2,3-dimethyl-3-(β,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dibromovinyl)-4-n-butyl-cyclobutanone,2,2-dimethyl-3-(α-chloro-β-acetoxyvinyl)-cyclobutanone,2,2-di-n-butyl-3-methyl-3-(α-chloro-β-cyanovinyl)-cyclobutane,2,2-dimethyl-3-(α-methylsulphonylvinyl)-cyclobutanone,2,2-diethyl-3-(β,β-dichlorovinyl)-4-cyclohexyl-cyclobutanone,2,3-dimethyl-2-chloro-3-(α,β,β-trichlorovinyl)-cyclobutanone,2-methyl-2-phenyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chloro-β-phenylvinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-bis-(trifluoromethyl)-vinyl)-cyclobutanone and2,2-dimethyl-3-(α,β,β-trichlorovinyl)-4-benzyl-cyclobutanone which aresubstituted in the 4-position by chlorine or bromine.

Spiro-cyclic cyclobutanones which are halogenated in the 3-position are:3-(β,β-dichlorovinyl)-spiro[3,5]nonan-1-one,3-(α,β,β-trichlorovinyl)-spiro[3,5]nonan-1-one,3-(β,β-dibromovinyl)-spiro[3,5]nonan-1-one,3-(β,β-dichlorovinyl)-spiro[3,4]octan-1-one,3-(β,β-dichlorovinyl)-2-methyl-spiro[3,5]nonan-1-one,3-(α,β-dichlorovinyl)-spiro[3,5]nonan-1-one and3-(α,β,β-trifluorovinyl)-spiro[3,5]nonan-1-one.

Alcoholates of the formula (III) which are preferably employed inprocess variant 1.1 are: alkali metal and alkaline earth metalalcoholates, such as, for example, sodium methylate, sodium ethylate,lithium n-propylate and potassium tert.-butylate. However, alkali metalalcoholates of higher alcohols, such as benzyl alcohols substituted inthe m-position by benzyl, furfuryl-3, furfuryl-2, m-fluorophenoxy,trichlorovinyloxy, phenoxy, β,β-dichlorovinyloxy, buta-1,3-dienyloxy orperchlorobuta-1,3-dienyloxy, or 4-phenyl-3,4-dichlorobut-2-enol,4-phenyl-4-methyl-but-2-enol, 4-phenyl-3-chloro-4-methyl-but-2-enol,vitamin A alcohol, 5,-dichloropenta-2,4-dienol, pyrethrenolone andα-ethynyl-m-phenoxybenzyl alcohol, also find use.

Alcoholates of the formula (III) in which R⁸ represents a radical of thegeneral formula ##STR17## in which

R^(a) represents hydrogen, cyano or ethynyl,

R^(b) represents hydrogen, a C₁₋₄ alkyl radical, a phenoxy, benzyl orphenylthio group, or a vinyl or buta-1,3-dienyl radical which isoptionally substituted by halogen,

R^(c) represents hydrogen, halogen or a C₁₋₄ alkyl radical and

R^(d) represents oxygen, sulphur or a vinylene group,

are particularly suitable.

The process variant 1.1 according to the invention is preferably carriedout in an inert organic solvent, such as methanol, if sodium methylateis used, or ethanol, if sodium ethylate is used, or an ether, such asdiethyl ether, tetrahydrofuran or 1,2-dimethoxyethane,tetramethylenesulphone, dimethylformamide or a hydrocarbon, such asbenzene or toluene. The reaction can be carried out at a temperature ofabout -30° to +150° C., preferably of about 20° to 60° C. Sometimes thecomponents already react with one another sufficiently rapidly at 0° C.The reaction time depends on the reactants, the reaction temperature andthe α-halogenoketone used, and can vary from about 1 to 10 hours.

Theoretically, one equivalent of an alcoholate is necessary for the ringcontraction. However, the reaction can also be carried out with anexcess of up to one equivalent of alcoholate or with an amount ofalcoholate which is slightly less than the equivalent amount, namelyabout 0.1 equivalent less.

For working up, any excess of the alcoholate which may be present isneutralized with, for example, alcoholic hydrochloric acid, whilecooling; the reaction mixture is then filtered and thecyclopropanecarboxylic acid ester is separated off by distillation orcrystallization of the filtrate. However, an alternative procedure is tointroduce the reaction mixture into hydrochloric acid, diluted with ice,and to extract the desired ester using an organic solvent.

(5) Cyclobutanones of the formula (IV) which can be used in processvariant 1.2 are known (J.Org. Chem. 32, 2704 (1967); Houben-Weyl, VolumeIV part 4, page 174 et seq.). They can be prepared in a simple manner by

(5.1) reacting an α-chloroenamine of the general formula ##STR18## inwhich

R⁵ and R⁶ have the meaning stated under 1 and

R¹⁰ and R¹¹, which may be identical or different, each represent C₁₋₄-alkyl or, with the adjacent N atom, form a heterocyclic ring whichoptionally also contains one or more further hetero-atoms,

with an olefin of the general formula ##STR19## in which

R¹ to R⁴ and R⁷ have the meanings stated under 1,

if appropriate in a diluent in the presence of a Lewis acid or a silversalt and subsequently hydrolyzing the product, if appropriate in thepresence of an aqueous base or acid, or by

(5.2) hydrolyzing an imonium salt of the general formula ##STR20## inwhich

R¹ to R⁷ have the meanings stated under 1,

R¹⁰ and R¹¹ have the meanings stated under 5.1 and

Z represents an equivalent of an anion,

if appropriate in a diluent and if appropriate in the presence of anaqueous base or acid, or by

(5.3) reacting a ketene of the general formula ##STR21## in which

R⁵ and R⁶ have the meanings stated under 1, with an olefin of thegeneral formula (XII)

in which

R¹ to R⁴ and R⁷ have the meaning indicated under 1,

if appropriate in the presence of a diluent and if appropriate in thepresence of a catalyst, or by

(5.4) reacting a ketene of the general formula ##STR22## in which

R⁷ has the meaning stated under 1,

with an olefin of the general formula ##STR23## in which

R¹ to R⁶ have the meanings stated under 1,

if appropriate in the presence of a diluent and if appropriate in thepresence of a catalyst, or by

(5.5) reacting a ketene acylal of the general formula ##STR24## in which

R⁵ and R⁶ have the meanings stated under 1, with an olefin of thegeneral formula (XII)

in which

R¹ to R⁴ and R⁷ have the meanings stated under 1,

if appropriate in a diluent and in the presence of a catalyst, or by

(5.6) halogenating the vinyl group of a cyclobutanone of the generalformula (IV)

in which

R¹ to R⁷ have the meaning stated under 1, provided that one of R¹ to R³is hydrogen,

if appropriate in a diluent, and subsequently dehydrohalogenating thereaction product, or by

(5.7) dehydrohalogenating a cyclobutanone of the general formula##STR25## in which

R¹ to R⁷ have the meanings stated under 1, but at least one of theradicals R¹ to R³ represents hydrogen,

if appropriate in a diluent, or by

(5.8) hydrolyzing an imonium salt of the general formula ##STR26## inwhich

R¹ to R⁷ have the meanings stated under 1,

R¹⁰, R¹¹ and Z have the meanings stated under 5.2 and

R¹² has the meaning stated under 1.3,

if appropriate in the presence of an aqueous base or acid andsubsequently dehydrohalogenating the product, or by

(5.9) reacting an α-chloroenamine of the general formula (XIII) in which

R⁵, R⁶, R¹⁰ and R¹¹ have the meanings stated under 5.1,

with an olefin of the general formula ##STR27## in which

R¹², R⁴ and R⁷ have the meanings stated under 1 and 1.3,

if appropriate in a diluent and in the presence of a Lewis acid or asilver salt, and subsequently hydrolyzing the product in the presence ofan aqueous acid or base.

(6) Those cyclobutanones of the formula (IV) (which can be used inprocess variant 1.2) are new wherein R¹ to R⁷ have the meanings statedunder 1 and at least one of the radicals R¹, R² and R³ to have a meaningother than hydrogen or methyl and R⁵ has a meaning other than phenyl.

Preferred cyclobutanones of the formula (IV) for use in process variant1.2 are those in which

R¹, R² and R³, which may be identical or different, each representhydrogen, halogen (especially chlorine or bromine), CN, straight-chain,branched or cyclic C₁₋₆ -alkyl or alkenyl [either of which may beoptionally substituted by halogen (especially fluorine or chlorine),C₁₋₄ -alkoxy, CN or C₁₋₄ -halogenoalkoxy], benzyl, phenylethyl, phenylor naphthyl [any of which may be optionally substituted by halogen(especially chlorine), C₁₋₄ -alkyl, C₁₋₄ -halogenoalkyl, NO₂ or CN],C₁₋₄ -alkoxycarbonyl, dialkylaminocarbonyl with 1-4 carbon atoms peralkyl moiety, C₁₋₄ -alkylsulphonyl (especially methylsulphonyl),phenylsulphonyl [optionally substituted by halogen, C₁₋₄ -alkyl, C₁₋₄-halogenoalkyl, NO₂ or CN] or C₁₋₄ -acyloxy, (especially acetoxy, ortrifluoroacetoxy), and

R⁴ to R⁷, which may be identical or different, each represent hydrogen,straight-chain, branched or cyclic C₁₋₆ -alkyl or alkenyl [either ofwhich is optionally substituted by halogen (especially fluorine orchlorine), C₁₋₄ -alkoxy or CN], halogen (especially chlorine orbromine), CN or benzyl, phenylethyl, phenyl or naphthyl [any of whichmay be optionally substituted by halogen (especially chlorine), C₁₋₄-alkyl, C₁₋₄ -halogenoalkyl, NO₂ or CN], it being possible for any ofthe pairs R¹ and R², R² and R³, R¹ and R⁴, R⁴ and R⁵, R⁴ and R⁷ and R⁵and R⁶, conjointly with the adjacent carbon atom(s), to form a 5 to7-membered carbocyclic ring.

Cyclobutanones in which the radicals R¹ to R⁷ have the meaning mentionedin process variant 1.1 as being especially preferred are particularlypreferably employed in process variant 1.2.

Individual cyclobutanones which are advantageously employed are thosefrom which the α-halogenocyclobutanones mentioned in process variant 1.1are derived.

Halogenating agents which can be used in process variant 1.2 are:bromine, chlorine, mixtures of bromine and chlorine, sulphuryl chloride,N-halogenoimides, such as, for example, N-bromosuccinimide, and2,4,4,5-tetrabromocyclohexa-2,5-dienone.

The following are preferably used: bromine, chlorine and mixtures ofbromine and chlorine.

In the halogenation, the cyclobutanones and the halogenating agent aregenerally employed in equivalent amounts or with a slight excess ofhalogenating agent of about 0.1 to 0.2 equivalent.

The procedure is to bring together the cyclobutanone, diluent andhalogenating agent and to allow the mixture to react. If appropriate, acatalyst, for example an acid, preferably HBr or acetic acid, is addedto the mixture in order to catalyze the reaction. An alternativeprocedure is to add the halogenating agent to the initially introducedcyclobutanone and diluent at the rate at which it is consumed. Ifappropriate, the halogenation can also be carried out without thepresence of a diluent.

Diluents which can be used in process variant 1.2 are inert organicsolvents, such as hydrocarbons, for example hexane, benzene or toluene,chlorinated hydrocarbons, such as methylene chloride or carbontetrachloride, ethers, such as diethyl ether, or esters, such as ethylacetate.

The halogenation in process variant 1.2 is carried out, in general, atabout 0° to 40° C., preferably at room temperature. The halogenation iscarried out, in general, under normal pressure. The hydrogen halidewhich may be formed during the reaction can be removed, if appropriate,by bubbling nitrogen through the reaction solution.

After the halogenation has ended, an alcoholate of the formula (III) isadded to the reaction solution without intermediate isolation of thereaction products. Alcoholates which can be used are preferably alkalimetal or alkaline earth metal alcoholates, especially sodium orpotassium alcoholates, of alcohols which have been indicated as beingpreferred in process variant 1.1.

The resulting reaction solution is added to a solution or suspension ofthe alcoholate in the corresponding alcohol or in an inert organicsolvent, as has been described above. However, it is also possible toadd a solution or suspension of the alcoholate to the resulting reactionsolution. The procedure is generally carried out at a temperature ofabout -30° to 150° C., preferably about 20° to 60° C. The reaction timecan vary from about 1 to 10 hours. The alcoholates are generally addedto the reaction solution in an at least equimolar ratio, butappropriately in about a 1.5 to 1.7 molar ratio.

For working up, the alcoholate, which is optionally present in excess,is neutralized with, for example, alcoholic hydrochloric acid, whilecooling; the reaction mixture is filtered and the resultingcyclopropanecarboxylic acid ester is separated off by distillation orcrystallization of the filtrate. However, an alternative procedure canbe to introduce the reaction mixture into hydrochloric acid, dilutedwith ice, and to extract the desired ester with an organic solvent.

The α-halogenocyclobutanones of the formula (V) which can be used inprocess variant 1.3 are new.

They are obtained by the process 3.3 described hereinbelow. However,they can also be obtained by halogenation or HCl addition to thecorresponding vinyl-substituted α-halogenocyclobutanones by methodswhich are in themselves known.

α-Halogenocyclobutanones of the formula (V) in which R¹ to R⁷ have themeanings mentioned above as being preferred or especially preferred inprocess variant 1.1 are preferably used in process variant 1.3.

Preferred alcoholates of the formula (III) which are used in processvariant 1.3 are those which are indicated above as being preferred inprocess variant 1.1.

The procedure for the ring contraction of the halogenated cyclobutanonein process variant 1.3 is identical to that described in process variant1.1. The alcoholates used are preferably those of C₁ -C₄ alcohols sinceone equivalent of the alcoholate is consumed for the dehydrohalogenationand does not lead to the formation of the ester. This would beuneconomical in the case of expensive alcohols.

In addition to the ring contraction described, a dehydrohalogenationtakes place in the side chain, and this requires a further equivalent ofalcoholate.

The cyclobutanones of the formula (VI) which can be used in processvariant 1.4 are new.

They can be prepared by processes 5.8 and 5.9 described herein below orare obtained by halogenating or adding HCl onto the correspondingvinyl-substituted cyclobutanones by processes which are in themselvesknown.

The cyclobutanones of the formula (VI), in which R¹ to R⁷ have thepreferred or especially preferred meanings indicated in process variant1.1, are preferably used in process variant 1.4.

Alcoholates of the formula (III) which are preferably used are the sameas those indicated in process variant 1.3.

The procedure in process variant 1.4 is identical to that described inprocess variant 1.2. As in process variant 1.3, a dehydrohalogenation ofthe side chain takes place simultaneously with the ring contraction inprocess variant 1.4 also.

The new vinyl-substituted cyclopropanecarboxylic acid esters of theformula (I) in which R¹ to R⁸ have the meaning indicated under 2 canalso be prepared by the process variants 2.1 to 2.4, which are alsoaccording to the invention.

The following may be mentioned as preferred new cyclopropanecarboxylicacid esters: the m-phenoxybenzyl ester of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2-ethyl-2-methyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid,2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(β,δ,δ-trichlorobuta-1,3-dienyl)-cyclopropanecarboxylicacid,1,2,2-trimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylicacid, 1,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylicacid,2,2-dimethyl-3-(α-chloro-β-methylsulphonyl-vinyl)-cyclopropanecarboxylicacid, 2,2-diethyl-3-methyl-3-(α-cyano-β,β-dibromovinyl)- and2-(α-fluoro-β,β-dichlorovinyl)-spiro[2,5]octane-1-carboxylic acid, themethyl esters of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2-methyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2-methyl-2-n-propyl-3-(α-fluoro-β,β-dibromovinyl)-cyclopropanecarboxylicacid,1,2,2-trimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylicacid, 1,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylicacid and2-ethyl-2-propyl-3-(β-bromo-α,β-dichlorovinyl)-cyclopropanecarboxylicacid, the ethyl esters of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-diethyl-3-(α,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid,2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-chloro-β-acetoxyvinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,1,2,2,3-tetramethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylicacid,2,2-dimethyl-3-(β,δ,δ-trichlorobuta-1,3-dienyl)-cyclopropanecarboxylicacid, 2-(α,β,β'-trichlorovinyl)-spiro[2,5]octane-1-carboxylic acid,2,2-dimethyl-3-(α-chloro-β-methylsulphonyl-vinyl)-cyclopropanecarboxylicacid and2,2-dimethyl-3-[α-chloro-β,β-bis-(trifluoromethyl)vinyl]-cyclopropanecarboxylicacid, the n-propyl esters of2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2-methyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,1,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid and2-(α,β,β-trichlorovinyl)-spirohexane-1-carboxylic acid, theα-cyano-m-phenoxybenzyl esters of2,2-diethyl-3-(α,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2-methyl-2-n-propyl-3-(α-fluoro-β,β-dibromovinyl)-cyclopropanecarboxylicacid,1,2,2,3-tetramethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylicacid, 2-(α,β,β-trichlorovinyl)-spiro[2,5]octane-1-carboxylic acid,1,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid and2,2-dimethyl-3-(α-chloro-β,β-bis-(trifluoromethyl)vinyl)-cyclopropanecarboxylicacid, the 5-benzyl-3-furylmethyl esters of2,2-diethyl-3-(α,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,1,2,2,3-tetramethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidand 2-(α,β,β-trichlorovinyl)-spiro[2,5]octane-1-carboxylic acid and the3,4,5,6-tetrahydrophthalimidomethyl esters of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acidand 2-(α,β,β-trichlorovinyl)-spiro[2,5]octane-1-carboxylic acid.

Cyclopropanecarboxylic acids of the formula (VII), or their salts, ortheir esters with C₁₋₃ -alcohols of the formula (VIII),

in which

R¹, R² and R⁴ to R⁷ have the preferred or especially preferred meaningsindicated in process variant 1.2 and R³ represents chlorine, bromine,CN, straight-chain, branched or cyclic alkyl with 2-6 carbon atoms orstraight-chain or cyclic alkyl which has up to 4 carbon atoms and issubstituted by halogen, especially fluorine or chlorine, CN or C₁₋₄-alkoxy,

are preferably employed in this process.

Individual cyclopropanecarboxylic acids, or their salts or their C₁₋₃-alkyl esters, which are advantageously employed are2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid ethylester, 2,2-dimethyl-3-(α,β-dichlorovinyl)-cyclopropanecarboxylic acid,2-trifluorovinyl-spiro[2,5]octane-1-carboxylic acid, sodium2,2-diethyl-3-(α,β,β-trifluorovinyl)-cyclopropane carboxylate,1,2,2-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidmethyl ester, lithium2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropane carboxylate,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid,sodium 2,2-dimethyl-3-(α-methylsulphonylvinyl)-cyclopropane carboxylateand2-methyl-2,3-diethyl-3-(α-fluoro-β,β-dibromovinyl)-cyclopropanecarboxylicacid ethyl ester.

Process variant 2.1 can be carried out by employing acyclopropanecarboxylic acid of the formula (VII) and an alcohol of theformula (VIII) in an at least equimolar ratio. In general, however, thereaction is carried out with an excess of alcohol.

Diluents which can be used are inert organic solvents.

Catalysts which can be used are acids, such as p-toluenesulphonic acid,benzenesulphonic acid, hydrochloric acid and sulphuric acid.

The reaction is in general, carried out at about 60° to 150° C.

Process variant 2.2 is carried out in general by reacting acyclopropanecarboxylic acid of the formula (VII) with an equimolaramount of an acid halide to give the carboxylic acid halide and reactingthis, without isolating it, with an alcohol of the formula (VIII) in thepresence of a tertiary base.

If appropriate, the formation of the acid chloride is carried out in thepresence of a diluent, such as benzene, toluene or methylene chloride,at a temperature of about 0° to 100° C.

Acid halides which may be used are thionyl chloride, phosphorustrichloride, phosphorus tribromide or benzoyl chloride.

According to process variant 2.3, the new cyclopropanecarboxylic acidesters of the general formula (I) are also obtainable by reacting a saltof the new cyclopropanecarboxylic acids with an alkylating agent, suchas, for example, a halide or sulphonate, in an inert diluent.

Suitable salts are, for example, the alkali metal or ammonium salts;alkylating agents are, for example, benzyl chloride, benzyl bromide,m-phenoxybenzyl bromide or vitamin A bromide.

Suitable diluents are dimethylformamide, acetonitrile, pentan-3-one oracetone.

In general, the reaction is carried out at a reaction temperature ofabout 20° to 100° C., preferably about 25° to 80° C. The working up canbe carried out by distillation after the salts which have precipitatedduring the reaction have been separated of; frequently water is added tothe reaction mixture, the product is taken up in a solvent which issubstantially water immiscible and the solvent is evaporated off. Theesters thus obtained can be purified by distillation. If high-boilingesters, which can undergo decomposition during distillation, areobtained, they are freed from residues of solvent or alkylating agent invacuo at temperatures of up to about 150° C.

According to process variant 2.3, the new cyclopropanecarboxylic acidesters of the general formula (I) in which R¹ to R⁸ have the meaningsindicated under 2 are also obtainable by reacting a salt of the newcyclopropanecarboxylic acids with an alkylating agent, such as, forexample, a halide or sulphonate, in an inert diluent.

Suitable salts are, for example, the alkali metal or ammonium salts;alkylating agents are, for example, benzyl chloride, benzyl bromide orm-phenoxybenzyl bromide.

Suitable diluents are dimethylformamide, acetonitrile, pentan-3-one, oracetone.

In general, the reaction is carried out at a reaction temperature ofabout 20° to 100° C., preferably about 25° to 80° C. The working up canbe carried out by distillation after the salts which have precipitatedduring the reaction have been separated off; frequently water is addedto the reaction mixture, the product is taken up in a solvent which issubstantially water immiscible and the solvent is evaporated off. Theesters thus obtained can be purified by distillation. If high-boilingesters, which can undergo decomposition during distillation, areobtained, they are freed from residues of solvent or alkylating agent invacuo at temperatures of up to 150° C.

According to process variant 2.4, the C₁₋₄ -alkyl esters of the newcyclopropanecarboxylic acids according to formula (VII) can betransesterified in a manner which is in itself known. Thus, for example,it can be advantageous initially to prepare a C₁ -C₄ alkyl ester,preferably the ethyl ester, of a new cyclopropanecarboxylic acid of thegeneral formula (VII) by reacting an α-halogenocyclobutanone of thegeneral formula (II) with a sodium alcoholate, for example sodiumethylate, and then to transesterify this lower alkyl ester with analcohol which is of interest biologically, using a basic catalyst. Basesfor this process are, for example, sodium alcoholates. Suchtransesterifications proceed between equimolar amounts of alcohol andester, but, in general, the alcohol is used in excess and the loweralcohol formed during the reaction, such as, for example, ethanol, isremoved by distillation. Solvents for the trans-esterification are, forexample, toluene or xylene.

(7) Vinyl-substituted cyclopropanecarboxylic acids, which can be used inprocess variants 2.1 and 2.2, of the formula (VI) in which the radicalsR¹ to R⁷ have the meanings stated under 1 are known (GermanOffenlegungsschrift (German Published Specification) No. 2,539,048, DOS(German Published Specification) No. 2,544,150 and Nature 244, 456,(1973)).

They can be prepared by

(7.1) reacting α-halogenocyclobutanones of the formula (II) in which R¹to R⁷ and Hal have the meanings stated under 1, with an aqueous base, ifappropriate in a diluent, or by

(7.2) halogenating cyclobutanones of the formula (IV) in which R¹ to R⁷have the meanings stated under 1, if appropriate in a diluent, andsubsequently reacting the product with an aqueous base.

(8) The new cyclopropanecarboxylic acids of the formula (VII) in whichR¹ to R⁷ have the meanings stated under 2 are preferably obtained bythis procedure.

Particularly preferably, the following new cyclopropanecarboxylic acidsmay be mentioned:2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-diethyl-3-(α,β-dichlorovinyl)-cyclopropanecarboxylic acid,2-ethyl-2-methyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acid,2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-chloro-β-acetoxyvinyl)-cyclopropanecarboxylic acid,2-methyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2-methyl-2-n-propyl-3-(α-fluoro-β,β-dibromovinyl)-cyclopropanecarboxylicacid, 2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylicacid, 1-ethyl-2,2-dimethyl-3-(α,β-dichlorovinyl)-cyclopropanecarboxylicacid,1,2,2,3-tetramethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylicacid, 2,2-dimethyl-3-(β,δ,δ-trichlorobuta-1,3-dienyl)-cyclopropanecarboxylic acid,2-(α,β,β-trichlorovinyl)-spiro[2,5]octane-1-carboxylic acid,2-(α,β,β-trifluorovinyl)-1-methyl-spiro[2,5]octane-1-carboxylic acid,1,2,2-trimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylicacid,2,2,3-trimethyl-3-(α-chloro-β,β-dicyanovinyl)-cyclopropanecarboxylicacid, 1,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylicacid, 2,2-dimethyl-3-(α-chloro-β-methoxycarbonyl)-cyclopropanecarboxylicacid,2,2-dimethyl-3-(α-chloro-β-methylsulphonyl-vinyl)-cyclopropanecarboxylicacid,2,2-diethyl-3-methyl-3-(α-cyano-β,β-dibromovinyl)-cyclopropanecarboxylicacid,2-ethyl-2-propyl-3-(β-bromo-α,β-dichlorovinyl)-cyclopropanecarboxylicacid,2,2-dimethyl-3-[α-chloro-β,β-bis-(trifluoromethyl)-vinyl]-cyclopropanecarboxylicacid, 2-(α-fluoro-β,β-dichlorovinyl)-spiro[2,5]octane-1-carboxylic acid,2-(α,β,β-trichlorovinyl)-spirohexane-1-carboxylic acid, 2,2-dimethyl-3-(α-chloro-β-dimethylaminocarbonyl-vinyl)-cyclopropanecarboxylic acidand 2-phenyl-3-(α,β,β-trichlorovinyl)-cyclopropane-carboxylic acid.

The new and known α-halogenocyclobutanones which are used as startingmaterials in process variants 1.1, 1.3 and in process 7.1 are obtainableby processes 3.1 to 3.3 and 4.1.

Cyclobutanones of the formula (IV) in which R¹ to R⁷ have the preferredand especially preferred meanings indicated under 1.1 are preferred andespecially preferred in process 3.1.

Individual cyclobutanones which may be mentioned and which can beemployed in process 3.1 are preferably those cyclobutanones from whichthe α-halogenocyclobutanones indicated under 1.1 are derived.

Suitable halogenating agents for process 3.1 are those mentioned inprocess variant 1.2. However, bromine or chlorine is preferably used.

If appropriate, process 3.1 is carried out in a diluent. Suitablediluents are inert organic aprotic solvents, such as, for example,hydrocarbons and chlorinated hydrocarbons, such as methylene chloride,carbon tetrachloride, chloroform, 1,2-dichloroethane, n-hexane orligroin; ethers, such as diethyl ether; and esters, such as ethylacetate. In addition to the aprotic solvents, protic solvents can alsobe used, such as, for example, formic acid, acetic acid, propionic acidor butyric acid. Moreover, these can catalyze the formation of theα-halogenocyclobutanone derivatives. Further suitable catalysts are, forexample, hydrogen halide acids, such as hydrogen chloride, hydrogenbromide or hydrogen iodide; mineral acids, such as, for example,sulphuric acid, perchloric acid or phosphoric acid; and also Lewisacids, such as aluminum trichloride, ferric chloride, zinc chloride ortitanium tetrachloride. If appropriate, the halogenation can also becatalyzed by UV light.

The reaction temperature for the halogenation can be chosen within awide range. The reaction can take place, both at -70° C. and at +80° C.,depending on the structure of the cyclobutanone derivative to behalogenated. A temperature range of about -10° to +40° C., preferablyabout 15° to 25° C., proves useful for the preparation. Specifically,the halogenation can be carried out by introducing the halogen into thereaction solution incrementally, the rate of the addition depending onthe conversion of the halogen, that is to say the addition of a furtheramount of halogen is made only when halogen which has previously beenintroduced has reacted. Another method used at times is to add togetherthe reactants (cyclobutanone derivative and halogen and, if appropriate,solvent and catalyst) and to allow them to react at 15° to 25° C. Afurther variant is to drive out part of the hydrogen halide, formedduring the reaction, from the reaction solution with nitrogen or toremove it by reaction with a basic compound, such as, for example,calcium carbonate or sodium carbonate.

The working up of the reaction solution can be so carried out that thehydrogen halide is driven out with nitrogen or air and the reactionsolution is employed direct, if necessary after removing excess halogenwith sodium thiosulphate, in process variant 1.1 or process 7.1,especially if, by reaction with an aqueous alkali metal base, thecorresponding cyclopropanecarboxylic acid is to be obtained or if, byreaction with an alkali metal salt of a C₁ -C₄ alcohol, such as ethanol,a cyclopropanecarboxylic acid ester of this C₁ -C₄ alcohol is to beobtained. The crude α-halogenoketone can be obtained free from hydrogenhalide by washing with water, if appropriate with the addition of asolvent which is immiscible with water, and can be isolated in the pureform by crystallization or distillation.

The cyclobutanones of the general formula (X) which can be used inprocess 3.2 are new.

They can be obtained by reacting known cyclobutenones (Houben-Weyl,Volume IV part 4, page 174 et seq.) with organo-metallic compounds, suchas ethynylmagnesium bromide or propargyllithium, with the addition ofcatalysts, such as copper salts, which promote a 1,4-addition.

The resulting 3-ethynylcyclobutanones are halogenated both in theα-position relative to the keto group and on the triple bond. It is alsopossible to add hydrogen halide onto the triple bond before thehalogenation and thus to obtain 1-halogenovinyl- or2-halogenovinyl-substituted cyclobutanones instead of1,2-dihalogenovinyl-substituted cyclobutanones.

The procedure of process 3.2 corresponds to that described in process3.1, with the proviso that, where appropriate, 2 equivalents ofhalogenating agent are necessary for the halogenation.

The cyclobutanones of the general formula (VI) which can be used inprocess 3.3 are new; they can be obtained by the process described under5.9.

The procedure of process 3.3 also corresponds to that described inprocess 3.1.

Some of the new α-halogenocyclobutanones of the formula (II) in which R¹to R⁷ have the meaning indicated under 4 can also be obtained, accordingto the invention, by process 4.1.

The 1,3-dienes employed in process 4.1 are known or can be obtained byknown methods. 1,3-Dienes of the formula (XII) in which R¹ to R⁷ havethe preferred meanings indicated under 1.1 are preferably employed.

1,3-Dienes of the formula (XII) in which R¹ to R⁷ have the especiallypreferred meaning indicated under 1.1 are particularly preferred.

Particularly suitable 1,3-dienes of the formula (XII) are thoseindicated in process 5.1.

Chloroketene, which can be used in process 4.1, is known; ifappropriate, it can be prepared in situ. With regard to the processconditions for this reaction, the conditions described in GermanOffenlegungsschrift (German Published Specification) No. 2,539,048 maybe referred to.

As already mentioned, some of the cyclobutanones which can be used inprocess variant 1.2 and processes 3.1 to 3.3 and 7.2 are new. Theirpreparation is carried out by processes 5.1 to 5.9. Starting materialsof the formulae (IV) (XII), (XIII), (XV), (XVI), (XVII), (XVIII), (XIX),(XX), (XXI), and (XXII) in which R¹ -R⁷ have the preferred andparticularly preferred meaning indicated under 1.1 are preferably andparticularly preferably employed in these processes. R¹⁰ and R¹¹preferably represent methyl or ethyl or, conjointly with the adjacent Natom, form a piperidine or morpholine ring.

The addition of a ketene or masked ketene (acylal or α-chloro-enamine)onto a double bond is common to processes 5.1 to 5.5 and 5.9.Cycloaddition reactions with ketenes to give 4-membered cyclic ketonesproceed strictly stereospecifically, but frequentlyregio-unspecifically. The more rich in electrons the double bond of theolefin, the more readily they occur. Thus, for example, dimethylketeneadds onto 1-dialkylaminoalkenes or 1-alkoxyalkenes considerably betterthan onto the corresponding unsubstituted alkene. The cycloaddition ofα-chloro-enamines on to 1,3-dienes having electron-attractingsubstituents, which proceeds unexpectedly smoothly, proves particularlyvaluable for the preparation. The cyclobutanones of the general formula(IV) are obtained in high yields under mild reaction conditions afterthe hydrolysis of the imonium salts which are formed as intermediates. Aparticular characteristic of this reaction is the observedregiospecificity of the addition. Indications of the formation of theregio-isomeric cyclobutanones are not obtained.

Specific examples of the α-chloro-enamines of the general formula (XIII)which are employed in process 5.1 are:1-chloro-1-dimethylamino-2-methyl-1-propene,1-chloro-1-piperidino-2-methyl-1-propene,1-chloro-1-diethylamino-2-methyl-1-propene,1-chloro-1-dimethylamino-1-propene,1-chloro-1-morpholino-2-methyl-1-propene,1-chloro-1-methylethylamino-2-methyl-1-propene,1-chloro-1-dimethylamino-2-ethyl-1-butene,1-chloro-1-dimethylamino-2-methyl-1-butene,(1-chloro-1-dimethylamino-methylene)-cyclohexane,1,2-dichloro-1-dimethylamino-2-methyl-1-propene and1-chloro-1-dimethylamino-2-methyl-2-phenyl-1-propene.

These α-chloro-enamines are known or can be prepared by known processes.

A large number of olefins of the general formula (XII) can be used asreactants in the cycloaddition reaction according to process 5.1, forexample: 1-chlorobuta-1,3-diene, 2-chlorobuta-1,3-diene,1,1-difluorobuta-1,3-diene, 1,1,2-trifluorobuta-1,3-diene,1,1,2-trichlorobuta-1,3-diene, 1,1-dichlorobuta-1,3-diene,1,1-dichloro-2-fluorobuta-1,3-diene,1,1-dichloro-2-methylbuta-1,3-diene, 1,1-dichloro-2-ethylbuta-1,3-diene,1,1-dichloro-3-methylbuta-1,3-diene,1,1,2-trifluoro-3-methylbuta-1,3-diene,1,1,2-trichloro-3-methylbuta-1,3-diene, 1,1-dicyanobuta-1,3-diene,1,1-dicyano-2-methylbuta-1,3-diene, 1,1-difluoro-2-chlorobuta-1,3-diene,1,1,2-trichloro-3-cyanobuta-1,3-diene,1,1-dichloro-2-bromobuta-1,3-diene, 2-chloro-3-methylbuta-1,3-diene,1,2-dichlorobuta-1,3-diene, 1,2-dibromobuta-1,3-diene,1,1-dibromobuta-1,3-diene, 1,1-dibromo-2-fluorobuta-1,3-diene,1,1-dibromo-2-chlorobuta-1,3-diene, 1,1-dichloropenta-1,3-diene,1,1-dichloro-hexa-1,3-diene, 1,1,2-trichloro-penta-1,3-diene,1,1-dichloro-3-methylpenta-1,3-diene,1,1,2-trichloro-3-methylpenta-1,3-diene, 1,1-dichloro-hepta-1,3-diene,1,1,2-trichloro-hepta-1,3-diene, 1,1-dichloro-octa-1,3-diene,1,1-dichloro-nona'-1,3-diene, 1,1-dibromo-penta-1,3-diene,1-acetoxy-2-chloro-buta-1,3-diene,1,1-bis-trifluoromethyl-buta-1,3-diene,2-methanesulphonyl-buta-1,3-diene, 1,1-dibromo-2-fluoro-penta-1,3-diene,1,1-dichloro-2-fluoro-penta-1,3-diene,1,3-dibromo-2-methyl-penta-1,3-diene,1-(β,β-dichlorovinyl)-1-cyclohexene, 1-vinyl-2-chloro-1-cyclohexene and1-(β,β-dichlorovinyl)-1-cyclopentene.

For process 5.1, it is necessary to convert the α-chloroenamine into areactive form. This can be carried out by reacting the α-chloro-enaminewith, for example, silver tetrafluoroborate. Other salts, such as, forexample, silver hexafluorophosphate, silver perchlorate or silverhexafluoroarsenate can be used. With regard to isolating thecyclobutanones of the general formula (IV), it is cheaper to use zincchloride for carrying out the cycloaddition reaction withα-chloro-enamines according to process 5.1. Thus, in the case ofaddition on to halogenovinyl-substituted olefins under the mild reactionconditions used (see below), no reaction of the zinc chloride with thediene takes place. However, a large number of other compounds, such as,for example, Lewis acids (iron III) chloride, titanium tetrachloride,aluminum chloride, boron trifluoride or tin chloride) can be used inprocess 5.1.

The reaction of an α-chloro-enamine of the general formula (XIII) withan olefin of the general formula (XII) can be carried out by initiallyintroducing the olefin, if appropriate in a solvent, together with aLewis acid and adding the α-chloro-enamine dropwise, if appropriate in asolvent, while stirring. An exothermic effect can occur in thisprocedure. However, an alternative procedure can be initially tointroduce the α-chloro-enamine, if appropriate in a solvent, to producethe reactive keteneimonium cation by adding a Lewis acid and to add theolefin dropwise, if appropriate in a solvent. An exothermic effect canalso occur in this procedure. A further variant is to add together thereactants (α-chloro-enamine, Lewis acid and olefin), if appropriate in asolvent, and to stir the mixture. An exothermic effect can again occurhere. Solvents which can be employed are halogenated hydrocarbons, suchas, for example, methylene chloride, chloroform, carbon tetrachloride,1,2-dichloroethane, 1,1,2,2-tetrachloroethane or 1,2-dichloroethylene,or acetonitrile, ethers or acetic acid esters, and also, for example,hydrocarbons, such as cyclohexane or petroleum ether, and alsotetramethylene-sulphone or dimethylformamide.

The cycloaddition of an α-chloro-enamine onto an olefin in the presenceof a Lewis acid is a reaction which proceeds stoichiometrically.However, it is advisable to employ a small excess of α-chloro-enamineand Lewis acid (maximum about 20%).

The reaction temperature can be chosen within a wide range. Thus, thereaction according to the invention can be carried out both at about-10° C. and +80° C. In many cases it has been shown that thecycloaddition reaction already occurs in the temperature range of 20° to40° C., which is easy to control industrially, that is to say at roomtemperature or slightly above. A reaction time of about 1/2 to 24 hoursis sufficient for a complete conversion.

For working up, the reaction mixture of process 5.1 is hydrolyzed byadding water, an aqueous base or an acid. In this procedure, thecyclobutanone-imonium salt, which is formed as an intermediate, isconverted into the cyclobutanone derivative of the general formula (IV),if appropriate by warming the solution to a temperature of about 20° to100° C., preferably about 40° to 60° C., and this cyclobutanonederivative is separated off by extraction with an organic solvent, suchas, for example, toluene or dibutyl ether. By means of fractionaldistillation, if appropriate under reduced pressure, and/orcrystallization it can be obtained in an analytically pure form forcharacterization. In many cases the purification is superfluous and thecrude cyclobutanone can be employed directly in process variant 1.2 orprocesses 7.2 or 3.1. A prerequisite for this is that the solvent usedfor the extraction or cycloaddition reaction does not react with thehalogenating agent.

The imonium salts which can be used in processes 5.2 or 5.8 are new;they are prepared by process 9.1 or 9.2 (see below).

Ketenes which can be used in processes 5.3 and 5.4 are known or can beprepared in a manner which is in itself known by (a) dehalogenating anα-halogenocarboxylic acid halide, for example α-bromoisobutyric acidbromide, in an inert solvent, such as, for example, ether or ethylacetate, with zinc, if appropriate activated zinc, in an inert gasatmosphere (nitrogen) and distilling off the ketone formed, togetherwith the inert solvent, the solvent and ketene being employed directlyfor the cycloaddition reaction (Houben-Weyl, Volume IV, part 4, page 174et seq.); or (b) dehydrohalogenating acid chlorides, for exampleisobutyric acid bromide, with a tertiary amine, such as, for example,triethylamine or dicyclohexyl-ethylamine; or (c) reacting anα-diazoketone with mercury oxide; or (d) dissociating a ketene dimer,for example 2,2,4,4-tetramethylcyclobutane-1,3-dione, by the action ofheat.

Ketene acetals which can be used in process 5.5 are known from GermanAuslegeschrift (German Published Specification) No. 1,199,259 and can beprepared by the processes described there.

The cyclobutanones which can be used in process 5.6 are new; they can beprepared by processes 5.1 to 5.5 and 5.8.

The cyclobutanones which can be used in process 5.7 are new; they can beprepared by adding halogen onto the vinyl group of cyclobutanones whichcan be prepared according to processes 5.1 to 5.5 and 5.8.

Process 5.9 can be carried out under the same conditions as indicatedfor process 5.1. The cyclobutanone-imonium salts formed as intermediatesin these processes are hydrolyzed, without isolating them, to thecorresponding cyclobutanones (see above).

The conversion, to be carried out in processes 5.2 and 5.8, of anisolated cyclobutanone-imonium salt of the general formulae (XV) and(XXI) into the corresponding cyclobutanone is carried out analogously tothe procedure described in process 5.1. The conversion can also becarried out by subjecting the reaction solution, which has optionallybeen acidified or rendered alkaline, to steam distillation andseparating off the cyclobutanone derivative from the steam distillate byextraction with an organic solvent and then, as given above, purifying.The zinc salts which remain in the aqueous phase, for example if dryzinc chloride is used as the Lewis acid, can be recovered by working up.

Processes 5.3 to 5.5 are carried out in an autoclave or bomb tube underpressure, for example analogously to the reaction conditions indicatedin German Offenlegungsschrift (German Published Specification) No.1,199,259.

(9) The imonium salts of the general formulae (XV) and (XXI) which canbe used in processes 5.2 and 5.8 are new. They are obtained when (9.1)an α-chloroenamine of the general formula (XIII) in which R⁵, R⁶, R¹⁰and R¹¹ have the meanings stated under 5.1, is reacted with an olefin ofthe formula (XIV) in which R¹ to R⁴ and R⁷ have the meanings statedunder 5.1, if appropriate in a diluent and in the presence of a silversalt, or when (9.2) an α-chloroenamine of the general formula (XIII), inwhich R⁵, R⁶, R¹⁰ and R¹¹ have the meanings stated under 5.1, is reactedwith an olefin of the formula (XXII) in which R¹ to R⁴ and R⁷ have themeanings stated under 5.9, if appropriate in a diluent and in thepresence of a silver salt.

The reaction in processes 9.1 and 9.2 is carried out as described forprocess 5.1. It is generally carried out in the presence of astoichiometric amount of a silver salt, such as silver perchlorate,silver hexafluorophosphate, silver hexafluoroarsenate or, preferably,silver tetrafluoroborate. After the addition reaction of theα-chloroenamine and the olefin has been carried out, which is effectedby a procedure analogous to that described in 5.1, the silver chlorideformed is filtered off, the solvent is distilled off from the filtrateand the residue is crystallized.

The vinyl-substituted cyclopropanecarboxylic acids, or their salts,which can be used for process variants 2.1 to 2.3 can be obtained byprocesses 7.1 or 7.2.

In process 7.1, the α-halogenoketone is reacted with water in thepresence of a base; the salt, which is formed, of thecyclopropanecarboxylic acid is separated off and the acid is liberatedby acidifying the alkaline solution with a mineral acid. This conversioncan be carried out, if appropriate, with the addition of a solvent, suchas, for example, toluene, methylene chloride, lower alcohols, such asethanol or isopropanol, or dibutyl ether.

The reaction temperature can be chosen relatively freely; it can beabout 0° to 100° C., preferably about 20° to 40° C. Alkali metal oralkaline earth metal hydroxides, such as sodium hydroxide, potassiumhydroxide, lithium hydroxide or barium hydroxide; or tertiary amines,such as triethylamine or triethanolamine, can be used as bases; sodiumhydroxide or potassium hydroxide is preferably employed.

At least two equivalents of a monoacidic base are necessary for completeconversion of the α-halogenocyclobutanone into the salt of thecyclopropane carboxylic acid. Consequently, the α-halogenoketone of thegeneral formula (II) is also reacted with about 2 to 8 equivalents,preferably about 2 to 4 equivalents, of a monoacidic base.

The liberation of the acid from its salt can be effected by addingaqueous mineral acid, such as, for example, hydrochloric acid, sulphuricacid or phosphoric acid. The resulting cyclopropanecarboxylic acid canbe purified by distillation or crystallization. In many cases, the acidsare obtained in such a pure form that they can be further processeddirectly.

In the procedure of process 7.2, a cyclobutanone of the general formula(IV) is initially halogenated. In this procedure, the reaction iscarried out as indicated in process 3.1.

As already mentioned, the cyclopropanecarboxylic acid esters obtainableby the processes according to the invention are suitable for combatinganimal pests and as intermediates for the preparation of activecompounds for combating animal pests.

The active compounds are well tolerated by plants, have a favorablelevel of toxicity to warm-blooded animals, and can be used for combatingarthropod pests, especially insects and acarids which are encountered inagriculture, in forestry, in the protection of stored products and ofmaterials, and in the hygiene field. They are active against normallysensitive and resistant species and against all or some stages ofdevelopment. The above-mentioned pests include: from the class of theIsopoda, for example Oniscus asellus, Armadillidium vulgare andPorcellio scaber; from the class of the Diplopoda, for example Blaniulusguttulatus; from the class of the Chilopoda, for example Geophiluscarpophagus and Scutigera spec.; from the class of the Symphyla, forexample Scutigerella immaculata; from the order of the Thysanura, forexample Lepisma saccharina; from the order of the Collembola, forexample Onychiurus armatus; from the order of the Orthoptera, forexample Blatta orientalis, Periplaneta americana, Leucophaea maderae,Blattella germanica, Acheta domesticus, Gryllotalpa spp., Locustamigratoria migratorioides, Melanoplus differentialis and Schistocercagregaria; from the order of the Dermaptera, for example Forficulaauricularia; from the order of the Isoptera, for example Reticulitermesspp.; from the order of the Anoplura, for example Phylloxera vastatrix,Pemphigus spp., Pediculus humanus corporis, Haematopinus spp. andLinognathus spp.; from the order of the Mallophaga, for exampleTrichodectes spp. and Damalinea spp.; from the order of theThysanoptera, for example Hercinothrips femoralis and Thrips tabaci;from the order of the Heteroptera, for example Eurygaster spp.,Dysdercus intermedius, Piesma quadrata, Cimex lectularius, Rhodniusprolixus and Triatoma spp.; from the order of the Homoptera, for exampleAleurodes brassicae, Bemisia tabaci, Trialeurodes vaporariorum, Aphisgossypii, Brevicoryne brassicae, Cryptomyzus ribis, Doralis fabae,Doralis pomi, Eriosoma lanigerum, Hyalopterus arundinis, Macrosiphumavenae, Myzus spp., Phorodon humuli, Rhopalosiphum padi, Empoasca spp.,Euscelis bilobatus, Nephotettix cincticeps, Lecanium corni, Saissetiaoleae, Laodelphax striatellus, Nilaparvata lugens, Aonidiella aurantii,Aspidiotus hederae, Pseudococcus spp. and Psylla spp.; from the order ofthe Lepidoptera, for example Pectinophora gossypiella, Bupaluspiniarius, Cheimatobia brumata, Lithocolletis blancardella, Hyponomeutapadella, Plutella maculipennis, Malacosoma neustria, Euproctischrysorrhoea, Lymantria spp., Bucculatrix thurberiella, Phyllocnistiscitrella, Agrotis spp., Euxoa spp., Feltia spp., Earias insulana,Heliothis spp., Laphygma exigua, Mamestra brassicae, Panolis flammea,Prodenia litura, Spodoptera spp., Trichoplusia ni, Carpocapsa pomonella,Pieris spp., Chilo spp., Pyrausta nubilalis, Ephestia kuehniella,Galleria mellonella, Cacoecia podana, Capua reticulana, Choristoneurafumiferana, Clysia ambiguella, Homona magnanima and Tortix viridana;from the order of the Coleoptera, for example Anobium punctatum,Rhizopertha dominica, Bruchidius obtectus, Acanthoscelides obtectus,Hylotrupes bajulus, Agelastica alni, Leptinotarsa decemlineata, Phaedoncochleariae, Diabrotica spp., Psylliodes chrysocephala, Epilachnavarivestis, Atomaria spp., Oryzaephilus surinamensis, Anthonomus spp.,Sitophilus spp., Otiorrhynchus sulcatus, Cosmopolites sordidus,Ceuthorrhynchus assimilis, Hypera postica, Dermestes spp., Trogodermaspp., Anthrenus spp., Attagenus spp., Lyctus spp., Meligethes seneus,Ptinus spp., Niptus hololeucus, Gibbium psylloides, Tribolium spp.,Tenebrio molitor, Agriotes spp., Conoderus spp., Melolontha melolontha,Amphimallon solstitialis and Costelytra zealandica; from the order ofthe Hymenoptera, for example Diprion spp., Hoplocampa spp., Lasius spp.,Monomorium pharaonis and Vespa spp.; from the order of the Diptera, forexample Aedes spp., Anopheles spp., Culex spp., Drosophila melanogaster,Musca spp., Fannia spp., Calliphora erythrocephala, Lucilia spp.,Chrysomyia spp., Cuterebra spp., Gastrophilus spp., Hyppobosca spp.,Stomoxys spp., Oestrus spp., Hypoderma spp., Tabanus spp., Tannia spp.,hortulanus Oscinella frit, Phorbia spp., Pegomyia hyoscyami, Ceratitiscapitata, Dacus oleae and Tipula paludosa; from the order of theSiphonaptera, for example Xenopsylla cheopis and Ceratophyllus spp.;from the class of the Arachnida, for example Scorpio maurus andLatrodectus mactans; from the order of the Acarina, for example Acarussiro, Argas spp., Ornithodoros spp., Dermanyssus gallinae, Eriophyesribis, Phyllocoptruta oleivora, Boophilus spp., Rhipicephalus spp.,Amblyomma spp., Hyalomma spp., Ixodes spp., Psoroptes spp., Chorioptesspp., Sarcoptes spp., Tarsonemus spp., Bryobia praetiosa, Panonychusspp. and Tetranychus spp..

When used against hygiene pests and pests of stored products, the activecompounds are distinguished by an excellent residual activity on woodand clay as well as a good stability to alkali on limed substrates.

The active compounds according to the instant invention can be utilized,if desired, in the form of the usual formulations or compositions withconventional inert (i.e. plant compatible or herbicidally inert)pesticide diluents or extenders, i.e. diluents, carriers or extenders ofthe type usable in conventional pesticide formulations or compositions,e.g. conventional pesticide dispersible carrier vehicles such as gases,solutions, emulsions, wettable powders, suspensions, powders, dustingagents, foams, pastes, soluble powders, granules, aerosols,suspension-emulsion concentrates, seed-treatment powders, natural andsynthetic materials impregnated with active compound, very fine capsulesin polymeric substances and in coating compositions, for use on seed,and formulations used with burning equipment, such as fumigatingcartridges, fumigating cans, fumigating coils and the like, as well asULV cold mist and warm mist formulations.

These are prepared in known manner, for instance by extending the activecompounds with conventional pesticide dispersible liquid diluentcarriers and/or dispersible solid carriers optionally with the use ofcarrier vehicle assistants, e.g. conventional pesticide surface-activeagents, including emulsifying agents and/or dispersing agents, whereby,for example, in the case where water is used as diluent, organicsolvents may be added as auxiliary solvents. The following may bechiefly considered for use as conventional carrier vehicles for thispurpose: aerosol propellants which are gaseous at normal temperaturesand pressures, such as halogenated hydrocarbons, e.g.dichlorodifluoromethane and trichloromethane, as well as butane,propane, nitrogen and carbon dioxide; inert dispersible liquid diluentcarriers, including inert organic solvents, such as aromatichydrocarbons (e.g. benzene, toluene, xylene, alkyl naphthalenes, etc.),halogenated, especially chlorinated, aromatic hydrocarbons (e.g.chlorobenzenes, etc.), cycloalkanes, (e.g. cyclohexane, etc.), paraffins(e.g. petroleum or mineral oil fractions), chlorinated aliphatichydrocarbons (e.g. methylene chloride, chloroethylenes, etc.), alcohols(e.g. methanol, ethanol, propanol, butanol, glycol, etc.) as well asethers and esters thereof (e.g. glycol monomethyl ether, etc.), amines(e.g. ethanolamine, etc.), amides (e.g. dimethyl formamide, etc.),sulfoxides (e.g. dimethyl sulfoxide, etc.), acetonitrile, ketones (e.g.acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone,etc.), and/or water; as solid carriers, ground natural minerals, such askaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite ordiatomaceous earth, and ground synthetic minerals, such ashighly-dispersed silicic acid, alumina and silicates; as solid carriersfor granules; crushed and fractionated natural rocks such as calcite,marble, pumice, sepiolite and dolomite, as well as synthetic granules ofinorganic and organic meals, and granules of organic material such assawdust, coconut shells, maize cobs and tobacco stalks; whereas thefollowing may be chiefly considered for use as conventional carriervehicle assistants, e.g. surface-active agents, for this purpose:emulsifying agents, such as non-ionic and/or anionic emulsifying agents(e.g. polyethylene oxide esters of fatty acids, polyethylene oxideethers of fatty alcohols, alkyl sulfates, alkyl sulfonates, arylsulfonates, albumin hydrolyzates, etc., and especially alkylarylpolyglycol ethers, magnesium stearate, sodium oleate, etc.); and/ordispersing agents, such as lignin, sulfite waste liquors, methylcellulose, etc.

Adhesives such as carboxymethylcellulose and natural and syntheticpolymers in the form of powders, granules or latices, such as gumarabic, polyvinyl alcohol and polyvinyl acetate, can be used in theformulations.

It is possible to use colorants such as inorganic pigments, for exampleiron oxide, titanium oxide and Prussian Blue, and organic dyestuffs,such as alizarin dyestuffs, azo dyestuffs and metal phthalocyaninedyestuffs, and trace nutrients such as salts of iron, manganese, boron,copper, cobalt, molybdenum and zinc.

Such active compounds may be employed alone or in the form of mixtureswith one another and/or with such solid and/or liquid dispersiblecarrier vehicles and/or with protection agents, such as otherinsecticides, or acaricides, nematicides, bactericides, rodenticides,herbicides, fertilizers, growth-regulating agents, etc., if desired, orin the form of particular dosage preparations for specific applicationmade therefrom, such as solutions, emulsions, suspensions, powders,pastes, and granules which are thus ready for use.

As concerns commercially marketed preparations, these generallycontemplate carrier composition mixtures in which the active compound ispresent in an amount substantially between about 0.1-95% by weight, andpreferably 0.5-90% by weight, of the mixture, whereas carriercomposition mixtures suitable for direct application or fieldapplication generally contemplate those in which the active compound ispresent in an amount substantially between about 0.0000001-100,preferably 0.01-10%, by weight of the mixture. Thus, the presentinvention contemplates overall compositions which comprise mixtures of aconventional dispersible carrier such as (1) a dispersible inert finelydivided carrier solid, and/or (2) a dispersible carrier liquid such asan inert organic solvent and/or water, preferably including asurface-active effective amount of a carrier vehicle assistant, e.g. asurface-active agent, such as an emulsifying agent and/or a dispersingagent, and an amount of the active compound which is effective for thepurpose in question and which is generally between about 0.0001-95%, andpreferably 0.01-95%, by weight of the mixture.

The active compounds can also be used in accordance with the well knownultra-low-volume process with good success, i.e. by applying suchcompound if normally a liquid, or by applying a liquid compositioncontaining the same, via very effective atomizing equipment, in finelydivided form, e.g. average particle diameter of from 50-100 microns, oreven less, i.e. mist form, for example by airplane crop sprayingtechniques. Only up to at most about a few liters/hectare are needed,and often amounts only up to about 15 to 1000 g/hectare, preferably 40to 600 g/hectare, are sufficient. In this process it is possible to usehighly concentrated liquid compositions with said liquid carriervehicles containing from about 20 to about 95% by weight of the activecompound or even the 100% active substance alone, e.g. about 20-100% byweight of the active compound.

Furthermore, the present invention contemplates methods of selectivelykilling, combating or controlling pests, e.g. insects, which comprisesapplying to at least one of correspondingly (a) such insects, and (b)the corresponding habitat thereof, i.e. the locus to be protected, e.g.to a growing crop, to an area where a crop is to be grown or to adomestic animal, a correspondingly combative or toxic amount, i.e. aninsecticidally effective amount, of the particular active compound ofthe invention alone or together with a carrier vehicle as noted above.The instant formulations or compositions are applied in the usualmanner, for instance by spraying, atomizing, vaporizing, scattering,dusting, watering, squirting, pouring, fumigating, and the like.

It will be realized, of course, that the concentration of the particularactive compound utilized in the admixture with the carrier vehicle willdepend upon the intended application. Therefore, in special cases it ispossible to go above or below the aforementioned concentration ranges.

The following preparative examples illustrate the processes according tothe invention. Where spectroscopic data are indicated, they relate, inthe case of IR spectra, to characteristic absorption maxima; in the caseof NMR spectra they also relate to tetramethylsilane as an internalstandard.

The symbols used denote: s=singlet, d=doublet, t=triplet, q=quartet,m=multiplet, br=broad and do=double.

EXAMPLE 1 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone

A solution of 10.0 g of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone-dimethylimoniumtetrafluoroborate in 200 ml of water was warmed to 40°-60° C. for 30minutes. An oil separated out which was extracted with methylenechloride. Drying the methylene chloride phase with sodium sulphate andconcentration gave 6.1 g (90%) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone.

EXAMPLE 2 Preparation of2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone

74.0 g (0.54 mol) of anhydrous zinc chloride were added to 56.0 g (0.45mol) of 1,1-dichlorobuta-1,3-diene in 400 ml of methylene chloride,while stirring, and 60.0 g (0.45 mol) of1-chloro-1-dimethylamino-2-methyl-1-propene in 300 ml of methylenechloride were then added dropwise, while stirring. During thisprocedure, the temperature of the reaction solution rose from 18° C.initially to 35°-40° C. After stirring for 2 hours under reflux, themixture was cooled to 20° C. and, after standing overnight (15 hours) at15° to 20° C., 1,200 ml of 1N NaOH were added dropwise, while stirring.300 ml of methylene chloride were added, the mixture was acidified with10% strength aqueous hydrochloric acid and the phases were separated.The organic phase was washed with water until it gave a neutralreaction, clarified over anhydrous sodium sulphate and evaporated. Thisgave 85.1 g of a yellow-brown oil, which was subjected to fractionaldistillation.

Yield: 73.5 g (84.5%) of a colorless oil of boiling point 100°-104°C./12 mm Hg; n_(D) ²⁰ =1.4912.

IR (CCl₄) 1,790 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.13 s (3H), 1.29 s (3H), 2.80-3.30 m (3H) and 5.90-6.10ppmm (1H).

C₈ H₁₀ Cl₂ O: (193.1); calculated C 49.76, H 5.22, Cl 36.73; found 49.8,5.33, 36.1.

EXAMPLE 3 Preparation of4-bromo-2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone

A solution of 1.6 g (0.01 mol) of bromine in 4.5 ml of glacial aceticacid was added dropwise at 20° C. to a solution of 1.95 g (0.01 mol) of2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone in 2 ml of glacialacetic acid at such a rate that the reaction solution was decolorizedbefore each addition of bromine. After subsequently stirring for 3 hoursat 20° C., the reaction mixture was added to ice. The oil which hadseparated out was taken up in methylene chloride, the methylene chloridesolution was washed with water until it gave a neutral reaction andclarified over anhydrous sodium sulphate and the organic phase wasconcentrated. This gave 2.72 g of a yellow-colored oil which, accordingto the NMR spectrum, no longer contained the starting ketone. Instead ofthis, signals occurred which indicated the presence of the twostereoisomeric4-bromo-2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanones.

EXAMPLE 4 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone-dimethylimoniumtetrafluoroborate

7.0 g (0.052 mol) of 1-chloro-1-dimethylamino-2-methyl-1-propane in 15ml of methylene chloride were added dropwise to a suspension of 10.2 g(0.052 mol) of silver tetrafluoroboratain 70 ml of methylene chlorideand 11.0 g (0.07 mol) of 1,1,2-trichlorobutadiene in the course of onehour at -60° C., while stirring. The reaction mixture was allowed towarm to 20°-25° C. and after being left to stand (15 hours) silverchloride was filtered off. Evaporation of the filtrate in vacuo left21.07 g of a cycloadduct which, when recrystallized twice fromchloroform/ether, gave 10.3 g of colorless crystals of melting point129°-131° C.

C₁₀ H₁₅ BCl₃ F₄ N: (342,4); Calculated C 35.08, H 4.42, N 4.09; Found35.1, 4.31, 4.14.

NMR (CD₃ CN): δ 1.40 s (3H), 1.63 s (3H), 3.45 m (6H) and 3.5-4.0 ppm m(3H).

EXAMPLE 5 Preparation of2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid

A mixture of the isomeric4-bromo-2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanones, obtained from0.01 mol of 2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone accordingto Example 3, was stirred with 15 ml of 2N NaOH overnight (15 hours) at20° C. The neutral products were extracted with ether, the alkalineaqueous phase was acidified with 10% strength aqueous hydrochloric acidand the acids were extracted with ether. Washing the ether extract withsaturated sodium chloride solution and subsequent clarification oversodium sulphate (anhydrous) gave, after evaporating the organic phase,1.35 g (65%) (relative to2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone employed) ofcrystalline 2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylicacid which, according to the NMR spectrum, was a 22:78 mixture of thecis-trans isomers. Fractional crystallization from n-hexane gavesterically homogeneous2,2-dimethyl-3-trans-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid ofmelting point 87° to 89° C.

IR (CCl₄) 1,705 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.20 s (3H), 1.32 s (3H), 1.55 d (1H, J=5.5 Hz) 2.25 dod(1H, J=8 Hz and 5.5 Hz), and 5.63 ppm d (1H, J=8 Hz).

After separating off the dominant trans-acid from a relatively largeamount of crude acid, the sterically homogeneous2,2-dimethyl-3-cis-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid wasobtained by fractional crystallization from pentane.

Melting point 92° to 94° C.

EXAMPLE 6 Preparation of2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid ethylester

A solution of 1.6 g (0.01 mol) of bromine in 5 ml of carbontetrachloride was added dropwise, to the point of decolorization, to1.95 g (0.01 mol) of 2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone in5 ml of carbon tetrachloride, which contained 5% of hydrogen bromide at25° C. The mixture was subsequently stirred for 2 hours, the hydrogenbromide formed was removed by passing a dry stream of nitrogen throughand the reaction solution was concentrated. The residue was taken up in15 ml of absolute ether and the ether solution was added dropwise to asuspension of 0.9 g of sodium ethylate in 10 ml of absolute ether, whilecooling with ice. The mixture was subsequently stirred for 2 hours andthe temperature of the reaction mixture was allowed to rise to 20° to25° C. The solution, which had an alkaline reaction, was neutralizedwith ethanolic hydrochloric acid and then added to ice. Extraction withether, clarification of the ether phase over anhydrous sodium sulphateand concentration gave, after fractional distillation, 1.4 g (61%) ofcolorless ethyl ester of boiling point 75° to 80° C./0.2-0.3 mm Hgwhich, according to the NMR spectrum (CDCl₃) was identical to a specimenprepared from 2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylicacid via the acid chloride.

EXAMPLE 7a Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone

A solution of 150 ml of dry methylene chloride and 45.0 g (0.336 mol) of1-chloro-1-dimethylamino-2-methyl-1-propene was added dropwise to amixture of 53.0 g (0.336 mol) of 1,1,2-trichlorobuta-1,3-diene, 55.0 g(0.405 mol) of anhydrous zinc chloride and 250 ml of dry methylenechloride; the temperature of the solution rose from 20° C. initially to35° C. The solution was stirred for 5 hours under reflux and allowed tocool to 20° C.; 850 ml of 1N NaOH were added dropwise at 20° C., whilestirring. After adding 800 ml of carbon tetrachloride, the phases wereseparated and the organic phase was washed with water until it gave aneutral reaction and clarified over anhydrous sodium sulphate.Evaporation of the solvent gave 68.1 g (89%) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone as a yellowish oil.

Boiling point 118°-121° C./12 mm Hg; n_(D) ²⁰ =1.512.

IR (CCl₄) 1,790 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.17 s (3H), 1.39 s (3H) and 3.30-3.80 ppm m (3H).

C₈ H₉ Cl₃ O: (227.5); calculated C 42.23, H 3.99, Cl 46.75; found 42.5,3.92, 46.2.

EXAMPLE 7b Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone (variation using aLewis acid)

In each case, 0.3 mol of the Lewis acid indicated below was suspended in160 ml of methylene chloride and a solution of 36.8 g (0.275 mol) of1-chloro-1-dimethylamino-2-methyl-1-propene in 40 ml of methylenechloride was added in the course of 30 minutes, while cooling (15° C.)and stirring. The mixture was heated to reflux for 5 hours, 300 ml ofwater were added, whilst cooling with ice, and the mixture was stirredfor 15 hours at 20° C. Separation of the phases and washing of theorganic phase with water until neutral, drying over sodium sulphate andconcentrating in vacuo gave the crude ketone which, in each case, wassubjected to fractional distillation.

The yields indicated below were obtained:

    ______________________________________                                        Lewis acid       Yield of ketone                                              ______________________________________                                        Zinc chloride      91.5%                                                      Aluminum chloride                                                                              66%                                                          Tin(II) chloride 61%                                                          Titanium(IV) chloride                                                                          71%                                                          Tin(IV) chloride 73%                                                          ______________________________________                                    

EXAMPLE 8 Preparation of2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone

58.0 g (0.336 mol) of 1,1,2-trichloro-3-methyl-buta-1,3-diene and 55.0 g(0.405 mol) of anhydrous zinc chloride in 250 ml of dry methylenechloride were heated under reflux with 45.0 g (0.336 mol) of1-chloro-1-dimethylamino-2-methyl-1-propene in 150 ml of dry methylenechloride for 4 hours and the mixture was then worked up according toExample 2. Fractional distillation gave 47.0 g (58%) of crystalline2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone of melting point42° to 44° C. (from n-hexane).

IR (CCl₄) 1,790 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.21 s (3H), 1.39 s (3H), 1.45 s (3H), 2.70 d (1H, J=17Hz) and 3.97 ppm d (1H, J=17 Hz).

C₉ H₁₁ Cl₃ O calculated C 44.76, H 4.59, Cl 44.03; found 44.6, 4.58,43.7.

The following cyclobutanones were prepared by the process described:

    ______________________________________                                                                    Physical                                          Example                     character-                                        No.      Compound           istics                                            ______________________________________                                         9       2,2-Diethyl-3-(β,β-dichloro-                                                           n.sub.D.sup.20 1.4963                                      vinyl)-cyclobutanone                                                 10       2-Ethyl-2-methyl-3-(β,β-                                                               n.sub.D.sup.20 1.4922                                      dichlorovinyl)-cyclo-                                                         butanone                                                             11       2,2-Diethyl-3-(α,β,β-                                                            n.sub.D.sup.20 1.5153                                      trichlorovinyl)-                                                              cyclobutanone                                                        12       2-Ethyl-2-methyl-3-(α,β,β-                                                       n.sub.D.sup.20 1.5141                                      trichlorovinyl)-cyclo-                                                        butanone                                                             13       3-(α,β,β-trichlorovinyl)-                                                        n.sub.D.sup.20 1.5379                                      spiro[3,5]-nonan-1-one                                               14       3-(β,β-dichlorovinyl)-                                                                 melting point                                              spiro[3,5]-nonan-1-one                                                                           59-60° C.                                  15       2,2,3-Trimethyl-3-(β,β-                                                                boiling point                                              dichlorovinyl)-cyclo-                                                                            118-121° C./                                        butanone           15 mm Hg                                          16       2,2-Dimethyl-3-(β-chloro-                                                                   n.sub.D.sup.20 1.4757                                      vinyl)-cyclobutanone                                                 17       2,2,4-Trimethyl-3-(β-                                                                       boiling point                                              ethoxycarbonylvinyl)-                                                                            86-98° C./0.075                                     cyclobutanone      mm Hg                                             ______________________________________                                    

In addition, the following cyclobutanones could be prepared:2,2-dimethyl-3-(α-methyl-β,β-dichlorovinyl)-cyclobutanone,2,2-diethyl-3-(α,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chlorovinyl)-cyclobutanone,2,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-difluorovinyl)-cyclobutanone,2-ethyl-2,3-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-diethyl-3-(β,β-dibromovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(β,β-dibromovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α-ethyl-β,β-dichlorovinyl)-cyclobutanone,2-ethyl-2,3-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone,3-(β,β-dichlorovinyl)-spiro[3,5]-nonan-1-one,2,2-dimethyl-3-(α,β-dibromovinyl)-cyclobutanone,3-(β,β-dibromovinyl)-spiro[3,5]-nonan-1-one,2,2-dimethyl-3-(β-bromo-β-chlorovinyl)-cyclobutanone,2,2-dimethyl-4-ethyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2,4-trimethyl-3-(α,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-4-n-butyl-3-(β,β-dichlorovinyl)-cyclobutanone and2-methyl-3-(α,β,β-trichlorovinyl)-cyclobutanone.

EXAMPLE 18 Preparation of4-bromo-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanon

A solution of 42.5 g (0.186 mol) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone, 31.1 g (0.194 mol)of bromine and 150 ml of 1% strength hydrobromic acid in carbontetrachloride was allowed to stand at 20° to 25° C. for 15 hours. Thehydrogen bromide formed was then driven out with nitrogen and thesolution was washed with water until it gave a neutral reaction,clarified over anhydrous sodium sulphate and concentrated. This gave56.7 g (quantitative) of crystalline4-bromo-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone which,according to the NMR spectrum, contained only one of the two isomericbromoketones.

Melting point 76° to 77° C. (from n-hexane).

IR (CCl₄) 1,800 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.25 s (3H), 1.50 s (3H), 3.74 d (1H, J=8.5 Hz) and 5.46ppm d (1H, J=8.5 Hz).

C₈ H₈ BrCl₃ O: (306.4); calculated C 31.36, H 2.63, Br 26.1, Cl 34.7;found 31.3, 2.70, 25.7, 34.3.

EXAMPLE 19 Preparation of4-bromo-2,2,4-trimethyl-3-(β,β-dichlorovinyl)-cyclobutanone

2.08 g (0.01 mol) of 2,2,4-trimethyl-3-(β,β-dichlorovinyl)-cyclobutanone(mixture of isomers) in 8 ml of glacial acetic acid were reacted with1.6 g (0.01 mol) of bromine according to Example 3. This gave, afterworking up, 2.65 g of a yellowish oil, the NMR spectrum (CDCl₃) of whichshowed the following signals: δ 1.20 s (3H), 1.34 s (3H), 1.39 s (3H),1.52 s (3H), 1.78 s (3H), 1.92 s (3H), 3.08 d (1H, J=8.5 Hz), 3.68 d(1H, J=9 Hz), 6.00 d (1H, J=9 Hz) and 6.26 ppm d (1H, J=8.5 Hz).

From the comparison of the intensities of the signals at δ 1.92/1.78,3.08/3.68 and 6.26/6.00 ppm, an isomer ratio of the4-bromo-2,2,4-trimethyl-3-(β,β-dichlorovinyl)-cyclobutanones of about3:2 was calculated.

EXAMPLE 20 Preparation of4-bromo-2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone

23.0 g (0.144 mol) of bromine were added to a solution of 33.6 g (0.14mol) of 2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 120 mlof carbon tetrachloride, which contained 1% of hydrobromic acid, at 20°C. After standing for 20 hours at 20° C., the solution was decolorized.It was worked up as described for Example 18 and 40.2 g (89%) of almosthomogeneous crystalline4-bromo-2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone wereisolated.

Melting point 81° to 82° C. (from n-hexane). According to the evidenceof the NMR spectrum of the crude product, only one of the isomericbromoketones was present.

IR (CCl₄) 1,800 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.31 s (3H), 1.47 s (6H) and 5.82 ppm s (1H).

C₉ H₁₀ BrCl₃ O: (320.5); calculated C 33.73, H 3.15, Br 24.9, Cl 33.2;found 34.0, 3.22, 24.4, 32.9.

The following α-bromocyclobutanones were prepared by the processdescribed:

    ______________________________________                                                                   Physical                                           Example                    character-                                         No.      Compound          istics                                             ______________________________________                                        21       4-Bromo-2,2-diethyl-3-                                                                          IR(CCl.sub.4) 1790 cm.sup.-1                                (α,β,β-trichlorovinyl)-                                       cyclobutanone                                                        22       4-Bromo-2-ethyl-2-methyl-                                                                       IR(CCl.sub.4) 1790 cm.sup.-1                                3-(α, β,β-trichlorovinyl)-                                    cyclobutanone                                                        23       2-Bromo-3-(α,β,β-tri-                                                           melting point                                               chlorovinyl)-spiro[3,5]                                                                         76-77° C.                                            nonan-1-one                                                          ______________________________________                                    

In addition, the following cyclobutanones could be brominated in the4-position: 2,2-dimethyl-3-(α-methyl-β,β-dichloro-vinyl)-cyclobutanone,2,2-diethyl-3-(α,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chlorovinyl)-cyclobutanone,2,2,3-trimethyl-3-(α,β,β-trifluorovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-difluorovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(β,β-dichlorovinyl)-cyclobutanone,2-ethyl-2,3-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-diethyl-3-(β,β-dibromovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(β,β-dibromovinyl)-cyclobutanone,2-ethyl-2-methyl-3-(α-fluoro-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α-ethyl-β,β-dichlorovinyl)-cyclobutanone,2-ethyl-2,3-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(β-bromo-β-chlorovinyl)-cyclobutanone,2,2-dimethyl-4-ethyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2,4-trimethyl-3-(α,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-4-n-butyl-3-(β,β-dichlorovinyl)-cyclobutanone,2-methyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-di-n-propyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2-hexyl-3-(β,β-dichlorovinyl)-cyclobutanone,2-methyl-2-butyl-3-(α,β,β-trichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-n-butyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chloro-β-methoxycarbonylvinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dicyanovinyl)-cyclobutanone,2,3-dimethyl-3-(β,β-dibromovinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-dibromovinyl)-4-n-butyl-cyclobutanone,2,2-di-n-butyl-3-methyl-3-(α-chloro-β-cyanovinyl)-cyclobutanone,2,2-dimethyl-3-(α-methylsulphonylvinyl)-cyclobutanone,2,2-diethyl-3-(β,β-dichlorovinyl)-4-cyclohexyl-cyclobutanone,2-methyl-2-phenyl-3-(β,β-dichlorovinyl)-cyclobutanone,2,2-dimethyl-3-(β-chloro-β-phenylvinyl)-cyclobutanone,2,2-dimethyl-3-(β,β-bis-(trifluoromethyl)-vinyl)-cyclobutanone,2,2-dimethyl-3-(α,β,β-trichlorovinyl)-4-benzyl-cyclobutanone and2-cyclohexyl-3-(β,β-dichlorovinyl)-cyclobutanone; and the followingspiro-cyclic cyclobutanones could be brominated in the 2-position: 3-(β,β-dichlorovinyl)-spiro[3,5]nonan-1-one,3-(β,β-dibromovinyl)-spiro[5,3]nonan-1-one,3-(β,β-dichlorovinyl)-spiro[4,3]octan-1-one,3-(β,β-dichlorovinyl)-2-methyl-spiro[5,3]nonan-1-one,3-(α,β-dichlorovinyl)-spiro[5,3]nonan-1-one and3-(α,β,β-trifluorovinyl)-spiro[3,5]nonan-1-one.

EXAMPLE 24 Preparation of4-chloro-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone

A total of 17 ml of previously condensed chlorine (about 0.3 mol) werepassed into a solution of 55.9 g (0.246 mol) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 200 ml of carbontetrachloride at 20° C., while stirring. After allowing to stand (15hours), hydrogen chloride and unreacted chlorine were removed by passingnitrogen into the reaction solution and the mixture was then extractedwith water, 5% strength sodium thiosulphate solution and again withwater. Drying the organic phase over sodium sulphate and concentrationgave 63.95 g of a crystalline product which was crystallized from 100 mlof n-hexane. Melting point 77°-78° C.

C₈ H₈ Cl₄ O: (262.0); Calculated C 36.68, H 3.08, Cl 54.14; Found 36.5,2.87, 53.8.

IR(CCl₄): 1810 cm⁻¹.

NMR (CDCl₃): δ=1.25 s (3H), 1.48 s (3H), 3.65 and 5.36 ppm AB quartet(J=8.5 Hz, 2H).

EXAMPLE 25 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid

58.6 g (0.26 mol) of crude2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 330 ml of carbontetrachloride, which contained 1% of hydrogen bromide, were allowed tostand at 20° C. with 41.5 g (0.26 mol) of bromine for 15 hours. Thehydrogen bromide formed was substantially driven out from thedecolorized solution and 570 ml of 1.3N NaOH were added to the solutionat 20° C. in the course of 2 hours, while stirring. After 6 hours, theorganic phase was separated off. Acidification of the aqueous alkalinephase with concentrated hydrochloric acid, while cooling, gave, afterextraction by shaking with ether, washing until neutral andclarification of the ether phase over anhydrous sodium sulphate, 56.6 g(89.3%) of crystalline2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid which,according to the NMR spectrum and within the accuracy of measurement,contained only one of the two isomers. Melting point 90° to 93° C. (frompetroleum ether).

EXAMPLE 26 Preparation of1,2,2-trimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid

The crude 4-bromo-2,2,4-trimethyl-3-(β,β-dichlorovinyl)-cyclobutanone(2.55 g) obtained according to Example 19 was suspended in 25 ml of 2NNaOH and the suspension was stirred at 20° C. for 6 hours. The mixturewas worked up as described for Example 5 to give 1.93 g (86%) (relativeto 0.01 mol of 2,2,4-trimethyl-3-(β,β-dichlorovinyl)-cyclobutanone) ofcrystalline 1,2,2-trimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylicacid as a mixture of isomers of melting point 87° to 95° C.

Fractional crystallization gave the homongenous isomers.

Isomer A

NMR (CDCl₃) δ 1.11 s (3H), 1.23 s (3H), 1.30 s (3H), 2.39 d (1H), J=7.5Hz), 5.63 d (1H, J=7.5 Hz) and 9.80 ppm s (1H).

Isomer B

NMR (CDCl₃) δ 1.30 s (6H), 1.45 s (3H), 1.68 d (1H, J=8.5 Hz), 6.26 s(1H, J=8.4 Hz) and 9.60 ppm s (1H).

EXAMPLE 27 Preparation of2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid

A suspension of 21.16 g (0.066 mol) of4-bromo-2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 150 mlof 1N NaOH was stirred for 10 hours at 20° C. The mixture was worked upas indicated for Example 5 to give 1.58 g of neutral products (unreactedbromoketone) and 13.73 g (87%) of crystalline2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid ofmelting point 152° to 153° C. (from benzene/n-hexane).

IR (CCl₄) 1700 cm⁻¹.

NMR (CDCl₃) δ 1.30 s (6H), 1.50 s (3H), 1.79 s and 1.95 s (1H) and 9.8ppm s (1H).

C₉ H₁₁ Cl₃ O₂ : (257.6); Calculated C 41.97, H 4.31, Cl 41.30; Found42.2, 4.33, 41.1.

EXAMPLE 28 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid

A suspension of 30.6 g (0.1 mol) of4-bromo-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 150 ml of2N NaOH was stirred at 20° to 25° C. for 10 hours. The homogeneoussolution was extracted with dibutyl ether in order to remove neutralproducts, acidified with 10% strength aqueous sodium chloride, whilecooling, and2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid, whichwas obtained in crystalline form, was filtered off and washed untilneutral.

Yield 23.8 g (about 100%).

IR (CCl₄) 1,705 cm⁻¹ (CO).

NMR (C₆ D₆) δ 0.86 s (1H), 1.16 s (1H), 1.99 d (1H, J=5.5 Hz), 2.34 d(1H, J=5.5 Hz) and 12.1 ppm s (1H).

C₈ H₉ Cl₃ O₂ calculated C 39.46, H 3.73, Cl 43.68; found 39.3, 3.81,43.4.

The following cyclopropane-carboxylic acids were prepared by the processdescribed:

    ______________________________________                                                                     Physical                                         Example                      character-                                       No.       Compound           istics                                           ______________________________________                                        29        2,2-Diethyl-3-(α,β,β-tri-                                                        melting point                                              chlorovinyl)-cyclopropane-                                                                       117-118° C.                                         cartoxylic acid                                                     30        2-Ethyl-2-methyl-3-(α,β,β-                                                       melting point                                              trichlorovinyl)-cyclo-                                                                           50-77° C.                                           propanecarboxylic acid                                              31        2-(α,β,β-trichlorovinyl)-                                                        melting point                                              spiro[2,5]octane-1-carboxy-                                                                      129-131° C.                                         lic acid                                                            ______________________________________                                    

In addition, the following cyclopropanecarboxylic acids could beprepared: 2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylicacid, 2,2-diethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2,3-trimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(β,β-dibromovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α,β-dibromovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-cyano-β,β-dichlorovinyl)-cyclopropanecarboxylic acid,1-ethyl-2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid,2-(β,β-dichlorovinyl)-spiro[2,5]octane-1-carboxylic acid,2,2-dimethyl-3-(β,β-dibromovinyl)-cyclopropanecarboxylic acid,2,2-dimethyl-3-(α-chloro-β,β-difluorovinyl)-cyclopropanecarboxylic acid,2-(β,β-dichlorovinyl-spiro[2,4]-heptane-1-carboxylic acid and2-methyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid.

EXAMPLE 32 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid

A suspension of 40.63 g (0.154 mol) of4-chloro-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 500 mlof 1N NaOH (0.5 mol) was stirred for 15 hours at 20°-25° C. Neutralproducts were separated off by extraction with ether and the alkalinesolution was acidified with hydrochloric acid, while cooling. Extractionwith ether, washing with water until neutral, drying over sodiumsulphate and evaporation in vacuo gave 23.1 g (62%) of colorlesscrystals of 2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylicacid of melting point 89°-91° C.

EXAMPLE 33 Preparation of2,2-dimethyl-3-(bromovinyl)-cyclopropanecarboxylic acid ethyl ester

32.0 g (0.2 mol) of bromine in 40 ml of carbon tetrachloride were addeddropwise to a solution of 12.4 g (0.1 mol) of2,2-dimethyl-3-vinylcyclobutanone in 100 ml of carbon tetrachloride at10° C. in the course of 2 hours. The mixture was subsequently stirredfor 1 hour, hydrogen bromide formed was dispelled with nitrogen and thesolution was washed successively with water, 1% strength aqueous sodiumthiosulphate solution and water, clarified over anhydrous sodiumsulphate and concentrated in vacuo. Yield: 31.83 g,

IR (CCl₄): 1805 cm⁻¹.

C₈ H₁₁ Br₃ O: (363); Calculated Br 66.2%; Found 65.3%.

A solution of 31.0 g of2,2-dimethyl-3-(α,β-dibromoethyl)-4-bromo-cyclobutanone in 40 ml ofabsolute ethanol was added dropwise to a solution of 4.6 g (0.2 mol) ofsodium in 70 ml of absolute ethanol at 0°-5° and the mixture wassubsequentlfy stirred for 1 hour at 40°-50°. Ethanolic hydrochloric acidwas added to the cooled solution in order to neutralize the excess base,the sodium bromide which had separated out was filtered off and thefiltrate was concentrated. Fractional distillation gave two mainfractions:

(A) 7.55 g of a colorless oil of boiling point 53°-58° C./0.2-0.3 mm Hg

IR (CCl₄): 1725 cm⁻¹ (ester-carbonyl).

NMR (CDCl₃): signals at, inter alia δ 5.52 (2 vinyl protons), 4.15 (2methylene protons of the ethyl group), 1.30 (3 methyl protons), 1.20 (3methyl protons) and 1.26 ppm (3 methyl protons of the ethyl group).

C₁₀ H₁₅ BrO₂ : (247.1); Calculated C 48.59, H 6.12, Br 32.34; Found48.6, 5.83, 32.2. (Calculated for2,2-dimethyl-3-(bromovinyl)-cyclopropanecarboxylic acid ethyl ester)

(B) 5.2 g of a colorless oil of boiling point 63°-70° C./0.1-0.3 mmg Hg.

According to the analytical data (IR, NMR and elementary analysis), thiswas a mixture of isomeric2,2-dimethyl-3-(bromovinyl)-cyclopropanecarboxylic acid ethyl esters.

EXAMPLE 34 Preparation of2-(α,β,β-trichlorovinyl)-spiro[2,5]octane-1-carboxylic acid ethyl ester

16.1 g (0.0463 mol) of2-bromo-3-(α,β,β-trichlorovinyl)-spiro[3,5]nonan-1-one in 80 ml of etherwere added dropwise to a solution of 1.07 g (0.0463 mol) of sodium in 20ml of ethanol in the course of 30 minutes at 15°-20° C., while stirringand cooling. After heating under reflux for one hour, the reactionmixture was poured onto ice and extracted with ether. Washing theorganic phase with saturated sodium bicarbonate solution and water,drying over sodium sulphate and subsequent concentration gave 13.3 g ofoil which was subjected to fractional distillation. This gave 11.3 g(78%) of ethyl ester of boiling point 116° C./0.15 mm Hg, n_(D) ²⁰ of1.5125.

C₁₃ H₁₇ Cl₃ O₂ : (311.7); Calculated C 50.1, H 5.5, Cl 34.1; Found 50.1,5.3, 33.9.

IR (CCl₄): 1735 cm⁻¹ (ester-carbonyl).

NMR (CDCl₃): δ=1.28 t (3H J=7.5 Hz), 1.3-2.0 m (10H), 2.05 and 2.48,AB-quartet (J=5.5 Hz, 2H) and 4.18 ppm q (2H J=7.5 Hz).

EXAMPLE 35 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid ethylester

7.66 g (0.025 mol) of4-bromo-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 40 ml ofdry ether were added dropwise to a suspension of 1.7 g (0.025 mol) ofsodium ethylate in 9 ml of anhydrous ethanol at 15° C. The mixture wassubsequently stirred for 1 hour at 15° C. and poured onto ice/1N HCl.The phases were separated, the aqueous phase was washed twice with etherand the combined ether extracts were then washed with aqueous sodiumbicarbonate solution and water until they gave a neutral reaction.Drying over anhydrous sodium sulphate gave 5.94 g (87%) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid ethylester.

Boiling point 73° to 74° C./0.2 mm Hg; n_(D) ²⁰ =1.4920.

IR (CCl₄) 1,726 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.20 s (3H), 1.30 t (3H, J=7.5 Hz), 1.33 s (3H), 2.04 d(1H, J=6 Hz), 2.45 d (1H, J=6 Hz) and 4.19 ppm q (2H, J=7.5 Hz).

0.9 g of 2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylicacid were obtained from the bicarbonate extract by acidification with10% strength hydrochloric acid and extraction with ether.

C₁₀ H₁₃ Cl₃ O₂ : (271.6); calculated C 44.23, H 4.83, Cl 39.17; found43.9, 5.09, 38.6.

The following esters could be prepared by the above process:2,2-dimethyl-3-(β,β-dibromovinyl)-cyclopropanecarboxylic acid ethylester, 2,2-dimethyl-3-(α,β,β-trifluorovinyl)-cyclopropanecarboxylic acidmethyl ester,2,2-diethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid ethylester, 2,2-diethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acidethyl ester,2,2,3-trimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acid ethylester, 1,2,2-trimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acidethyl ester, 2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylicacid methyl ester, 2-(β,β-dichlorovinyl)-spiro[2,5]octane-1-carboxylicacid ethyl ester and2-methyl-2-ethyl-3-(β,β-dichlorovinyl)-cyclopropanecarboxylic acidn-propyl ester.

EXAMPLE 36 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidm-phenoxybenzyl ester

A solution of 12.2 g (0.05 mol) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid and6.85 g (0.0575 mol) of thionyl chloride in 50 ml of dry benzene washeated under reflux for 1.5 hours. Excess thionyl chloride and gaseousreaction products were removed under a waterpump vacuum. 20 ml of drybenzene, 15 ml of dry pyridine and 8.0 g (0.04 mol) of m-phenoxy-benzylalcohol were added successively to the resulting residue. After standingfor 15 hours at 20° C., the reaction mixture was poured onto ice, withthe addition of 100 ml of benzene, and the benzene phase was separatedoff and washed successively with dilute hydrochloric acid, water, 2N Na₂CO₃ and water. Drying over sodium sulphate and evaporation gave 16.5 gof a colorless oil which, in order to separate off unreactedm-phenoxybenzyl alcohol, was dissolved in 100 ml of n-hexane andfiltered through 50 g of silica gel. Distillation in a bulb tube gave14.7 g of 2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylicacid m-phenoxybenzyl ester as a colorless oil of boiling point 190° to195° C./0.01 mm Hg. The ester proved to be homogeneous in analysis bythin-layer chromatography.

IR (CCl₄) 1,735 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.18 s (3H), 1.27 s (3H), 2.07 d (1H, J=6 Hz), 2.44 d (1H,J=6 Hz), 5.12 s (2H) and 6.90-7.50 ppm m (9H).

C₂₁ H₁₉ Cl₃ O₃ : (425.5); calculated C 59.1, H 4.46, Cl 25.0; found59.2, 4.70, 25.1.

The aqueous phase which resulted during the working up was acidifiedwith dilute hydrochloric acid and 1.45 g of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acid wererecovered by extraction with ether.

EXAMPLE 37 Preparation of2,2-dimethyl-3-(α-bromo-β,β-dichlorovinyl)-cyclopropanecarboxylic acidethyl ester

A solution of 3.2 g (0.02 mol) of bromine in 5 ml of carbontetrachloride was added dropwise to 1.95 g (0.01 mol) of2,2-dimethyl-3-(β,β-dichlorovinyl)-cyclobutanone in 5 ml of carbontetrachloride, which contained 5% of hydrogen bromide, at 25° C. Themixture was subsequently stirred for 6 hours, hydrogen bromide which hadformed was removed by passing a dry stream of nitrogen through and thereaction solution was concentrated. The residue, the NMR spectrum(CDCl₃) of which, in agreement with the bromination of the dichlorovinylgroup by the second mol equivalent of bromine, showed no signal for avinyl proton, was dissolved in 30 ml of ether and the solution was addeddropwise to a solution of 0.7 g (about 0.03 mol) of sodium in 30 ml ofabsolute ethanol at 20° to 25° C. The mixture was allowed to reactfurther for 1 hour at 60° C. and was worked up as described for Example6. This gave 2.19 g (69%) of2,2-dimethyl-3-(α-bromo-β,β-dichlorovinyl)-cyclopropanecarboxylic acidethyl ester of boiling point 85° to 90° C./0.3 mm Hg.

Calculated Br 25.3; Found 25.0.

EXAMPLE 38 Preparation of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidm-phenoxybenzyl ester

5.0 g (0.025 mol) of m-phenoxybenzyl alcohol were added to a solution of0.520 g (0.0226 mol) of sodium in 10 ml of absolute ethanol, undernitrogen, and the ethanol was distilled off in vacuo. Two 50 ml portionsof absolute toluene were added to the residue and the mixture wasevaporated to dryness in vacuo. 5.75 g (0.019 mol) of4-bromo-2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclobutanone in 20 ml ofabslute toluene were added dropwise to a suspension of the resultingsolid residue in 30 ml of absolute toluene at 15° C. and the mixture wassubsequently stirred for 6 hours at 20° C. According to analysis by thinlayer chromatography, complete conversion had taken place. The reactionmixture was added to ice/dilute hydrochloric acid and the organic phasewas separated off, washed until it gave a neutral reaction and filteredover 100 g of silica gel.

Yield: 5.12 g (60%) of2,2-dimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidm-phenoxybenzyl ester.

According to analysis by thin layer chromatography and the NMR spectrum,the product was identical to the product obtained in Example 36.

EXAMPLE 39 Preparation of2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidm-phenoxybenzyl ester

10.3 g of2,2,3-trimethyl-3-(β,β,β-trichlorovinyl)-cyclopropanecarboxylic acid(0.04 mol) were reacted, according to Example 36, with 5.8 g (0.048 mol)of thionyl chloride in 50 ml of dry benzene to give the acid chloride.25 ml of benzene, 15 ml of pyridine and 8.0 g (0.04 mol) ofm-phenoxybenzyl alcohol were added successively to the crude acidchloride. After standing for 10 hours at 20° C., the mixture was workedup according to Example 36 to give 16.2 g of crude ester. Chromatographyto silica gel and fractional distillation gave 13.1 g (74%) of2,2,3-trimethyl-3-(α,β,β-trichlorovinyl)-cyclopropanecarboxylic acidm-phenoxybenzyl ester as a colorless oil of boiling point 200° to 210°C./0.1-0.15 mm Hg.

IR (CCl₄) 1,730 cm⁻¹ (CO).

NMR (CDCl₃) δ 1.24 s (3H), 1.29 s (3H), 1.45 s (3H), 1.87 s and 1.99 s(1H), 5.10 s (2H) and 6.80-7.50 ppmm (9H).

C₂₂ H₂₁ Cl₃ O₃ Calculated C 60.08, H 4.81, C 24.19; Found 60.4, 4.65,24.0.

It will be appreciated that the instant specification and examples areset forth by way of illustration and not limitation, and that variousmodifications and changes may be made without departing from the spiritand scope of the present invention.

What is claimed is:
 1. A process for the preparation of anα-halogenocyclobutanone of the formula ##STR28## in which R¹, R² and R³each independently is hydrogen, halogen, CN, optionally substitutedalkyl, or alkenyl, aralkyl, aryl, alkoxycarbonyl, alkylsulphonyl,arylsulphonyl, acyloxy or dialkylaminocarbonyl, at least one of theradicals R¹, R² and R³ containing hydrogen,R⁴, R⁵, R⁶ and R⁷ eachindependently is hydrogen, optionally substituted alkyl or alkenyl,halogen, CN, aralkyl or aryl, or any of the pairs R¹ and R², R² and R³,R¹ and R⁴, R⁴ and R⁵, R⁴ and R⁷ and R⁵ and R⁶, conjointly with theadjacent carbon atoms or atoms from a carbocyclic ring with up to 8 ringcarbon atoms, and Hal is halogen, comprising to produce a cyclobutanoneof the formula ##STR29## and brominating the cyclobutanone.